<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2024 Workiva-->
<!--r:82144743-4964-42d4-8053-f8b752bc459a,g:6eac1007-0ae2-46c5-bdff-c1c45555700b-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.cmegroup.com/role/CoverPage" xlink:type="simple" xlink:href="cme-20231231.xsd#CoverPage"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/CoverPage" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_c1dc45fa-ca65-4d22-8219-ac71874ab16a" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntitiesTable_c1dc45fa-ca65-4d22-8219-ac71874ab16a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_41fff425-719e-418f-9d7c-99c606048949" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_c1dc45fa-ca65-4d22-8219-ac71874ab16a" xlink:to="loc_us-gaap_StatementClassOfStockAxis_41fff425-719e-418f-9d7c-99c606048949" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_41fff425-719e-418f-9d7c-99c606048949_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_41fff425-719e-418f-9d7c-99c606048949" xlink:to="loc_us-gaap_ClassOfStockDomain_41fff425-719e-418f-9d7c-99c606048949_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_2f32d452-4e49-4cc8-a1d3-4c78b027df2b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_41fff425-719e-418f-9d7c-99c606048949" xlink:to="loc_us-gaap_ClassOfStockDomain_2f32d452-4e49-4cc8-a1d3-4c78b027df2b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_2364814e-04ec-4c01-aafa-5e7b94ad58b7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_2f32d452-4e49-4cc8-a1d3-4c78b027df2b" xlink:to="loc_us-gaap_CommonClassAMember_2364814e-04ec-4c01-aafa-5e7b94ad58b7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClassBCommonStockClassB1Member_5ab357ec-fff4-4445-8ffe-7ac2262de8db" xlink:href="cme-20231231.xsd#cme_ClassBCommonStockClassB1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_2f32d452-4e49-4cc8-a1d3-4c78b027df2b" xlink:to="loc_cme_ClassBCommonStockClassB1Member_5ab357ec-fff4-4445-8ffe-7ac2262de8db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClassBCommonStockClassB2Member_313a1832-206a-4878-894e-28daac880a35" xlink:href="cme-20231231.xsd#cme_ClassBCommonStockClassB2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_2f32d452-4e49-4cc8-a1d3-4c78b027df2b" xlink:to="loc_cme_ClassBCommonStockClassB2Member_313a1832-206a-4878-894e-28daac880a35" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClassBCommonStockClassB3Member_2f11b37f-98eb-468f-9a8f-a350e6095a07" xlink:href="cme-20231231.xsd#cme_ClassBCommonStockClassB3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_2f32d452-4e49-4cc8-a1d3-4c78b027df2b" xlink:to="loc_cme_ClassBCommonStockClassB3Member_2f11b37f-98eb-468f-9a8f-a350e6095a07" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClassBCommonStockClassB4Member_4ec27550-2322-44de-9439-388e2a1e1776" xlink:href="cme-20231231.xsd#cme_ClassBCommonStockClassB4Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_2f32d452-4e49-4cc8-a1d3-4c78b027df2b" xlink:to="loc_cme_ClassBCommonStockClassB4Member_4ec27550-2322-44de-9439-388e2a1e1776" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_b5fd77de-9ce8-453d-9da5-9afc3f5e6cd8" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_DocumentType_b5fd77de-9ce8-453d-9da5-9afc3f5e6cd8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentAnnualReport_916287d2-46ec-43c4-832a-815aa0654ca6" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_DocumentAnnualReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_DocumentAnnualReport_916287d2-46ec-43c4-832a-815aa0654ca6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_06fa6eaf-0d60-409d-9f3d-d9bb382f1922" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_DocumentPeriodEndDate_06fa6eaf-0d60-409d-9f3d-d9bb382f1922" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_e32498af-f601-49ee-9c14-f6ac6c8a7795" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_DocumentTransitionReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_DocumentTransitionReport_e32498af-f601-49ee-9c14-f6ac6c8a7795" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_4936e4fa-b890-449a-a52f-0406fb15308c" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityFileNumber_4936e4fa-b890-449a-a52f-0406fb15308c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_89f1cc9f-da2b-4ce7-adf0-74534186688e" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityRegistrantName_89f1cc9f-da2b-4ce7-adf0-74534186688e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_5edb852a-da5a-4f77-b8bd-d9a655c488e6" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityIncorporationStateCountryCode_5edb852a-da5a-4f77-b8bd-d9a655c488e6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_c6ff8193-7d72-4229-b96d-fe9deda9b1e9" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityTaxIdentificationNumber_c6ff8193-7d72-4229-b96d-fe9deda9b1e9" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_a6c291a5-b009-4c48-b988-0fcce8420b03" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityAddressAddressLine1_a6c291a5-b009-4c48-b988-0fcce8420b03" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_52d1f9a4-b7c0-4b83-89da-0e21e5f107d0" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityAddressCityOrTown_52d1f9a4-b7c0-4b83-89da-0e21e5f107d0" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_e0f55827-2947-4f09-bbd1-e4f0965ef168" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityAddressStateOrProvince_e0f55827-2947-4f09-bbd1-e4f0965ef168" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_b495395f-fb21-4c25-af4b-48fc148f2ff6" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityAddressPostalZipCode_b495395f-fb21-4c25-af4b-48fc148f2ff6" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_853012b4-e79d-4570-b710-4d7609d80f95" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_CityAreaCode_853012b4-e79d-4570-b710-4d7609d80f95" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_3547ee09-5946-4625-ac13-6a78a11510f6" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_LocalPhoneNumber_3547ee09-5946-4625-ac13-6a78a11510f6" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_339b210a-5f5b-46aa-90b1-79ed24ce23de" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_Security12bTitle_339b210a-5f5b-46aa-90b1-79ed24ce23de" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_ecb6a6f3-4da3-42b1-912a-f240590b19b9" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_SecurityExchangeName_ecb6a6f3-4da3-42b1-912a-f240590b19b9" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityWellKnownSeasonedIssuer_31f7d7d5-73f8-4d0c-bb9f-1d875cdefba1" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityWellKnownSeasonedIssuer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityWellKnownSeasonedIssuer_31f7d7d5-73f8-4d0c-bb9f-1d875cdefba1" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityVoluntaryFilers_98e5e607-b7ff-4ca5-8447-7b1f3ec3d23f" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityVoluntaryFilers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityVoluntaryFilers_98e5e607-b7ff-4ca5-8447-7b1f3ec3d23f" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_99f3f3ba-c623-4b19-919a-11a480217e9b" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityCurrentReportingStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityCurrentReportingStatus_99f3f3ba-c623-4b19-919a-11a480217e9b" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_4653bfc7-7dc4-4e0a-817e-4da0858f8b00" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityInteractiveDataCurrent_4653bfc7-7dc4-4e0a-817e-4da0858f8b00" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_3041dec9-7b67-4313-ad24-bb8ff2d12f6a" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityFilerCategory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityFilerCategory_3041dec9-7b67-4313-ad24-bb8ff2d12f6a" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_8ff81981-6f03-4aab-be77-9e4b54183523" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntitySmallBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntitySmallBusiness_8ff81981-6f03-4aab-be77-9e4b54183523" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_d9b78956-86e6-4a3b-a583-4ed0429d6410" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityEmergingGrowthCompany_d9b78956-86e6-4a3b-a583-4ed0429d6410" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_IcfrAuditorAttestationFlag_b6e0bbdb-21f5-4ddc-aafd-984045f5158a" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_IcfrAuditorAttestationFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_IcfrAuditorAttestationFlag_b6e0bbdb-21f5-4ddc-aafd-984045f5158a" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_9a602b70-22a3-42da-8230-be11bc86bcd4" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityShellCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityShellCompany_9a602b70-22a3-42da-8230-be11bc86bcd4" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityPublicFloat_c21a5657-1174-4248-91a5-687a8029bd8c" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityPublicFloat"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityPublicFloat_c21a5657-1174-4248-91a5-687a8029bd8c" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_ab26431b-d13e-4509-b7c9-33d097d63f9a" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_ab26431b-d13e-4509-b7c9-33d097d63f9a" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentsIncorporatedByReferenceTextBlock_e92ba693-9b35-4744-86ea-4047c5cdf643" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_DocumentsIncorporatedByReferenceTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_DocumentsIncorporatedByReferenceTextBlock_e92ba693-9b35-4744-86ea-4047c5cdf643" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_b481f2b3-c03e-449c-8205-19821ceaf91f" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_EntityCentralIndexKey_b481f2b3-c03e-449c-8205-19821ceaf91f" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_b760ef52-a018-4426-a1d2-274d8efb5ffb" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_CurrentFiscalYearEndDate_b760ef52-a018-4426-a1d2-274d8efb5ffb" xlink:type="arc" order="29"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_c98b3094-a0e8-43d9-8880-6905a57011ee" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_DocumentFiscalYearFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_DocumentFiscalYearFocus_c98b3094-a0e8-43d9-8880-6905a57011ee" xlink:type="arc" order="30"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_afddce1f-f0c2-41e9-840f-0c56d56827fa" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_DocumentFiscalPeriodFocus_afddce1f-f0c2-41e9-840f-0c56d56827fa" xlink:type="arc" order="31"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_4cced3ba-4f12-47e0-9186-628b0b3eecec" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_TradingSymbol_4cced3ba-4f12-47e0-9186-628b0b3eecec" xlink:type="arc" order="32"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_b0eddff6-67a0-432f-85eb-d97834103f80" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_AmendmentFlag_b0eddff6-67a0-432f-85eb-d97834103f80" xlink:type="arc" order="33"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFinStmtErrorCorrectionFlag_cee13180-9f92-4f55-9eda-501728353150" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_DocumentFinStmtErrorCorrectionFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_732e4cd8-8a11-4299-8f8c-44ab4d03e60e" xlink:to="loc_dei_DocumentFinStmtErrorCorrectionFlag_cee13180-9f92-4f55-9eda-501728353150" xlink:type="arc" order="34"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/CONSOLIDATEDBALANCESHEETS" xlink:type="simple" xlink:href="cme-20231231.xsd#CONSOLIDATEDBALANCESHEETS"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/CONSOLIDATEDBALANCESHEETS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_5b6261e6-b763-4c1e-bebc-ffb740e98d89" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_887960cd-0060-4b24-a139-09030b712c81" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_5b6261e6-b763-4c1e-bebc-ffb740e98d89" xlink:to="loc_us-gaap_StatementTable_887960cd-0060-4b24-a139-09030b712c81" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_e8b3e678-a8a4-4591-98cf-c1f46680bce0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_887960cd-0060-4b24-a139-09030b712c81" xlink:to="loc_us-gaap_StatementClassOfStockAxis_e8b3e678-a8a4-4591-98cf-c1f46680bce0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_e8b3e678-a8a4-4591-98cf-c1f46680bce0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_e8b3e678-a8a4-4591-98cf-c1f46680bce0" xlink:to="loc_us-gaap_ClassOfStockDomain_e8b3e678-a8a4-4591-98cf-c1f46680bce0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_6647c5c8-3413-4259-8182-07bf69f04988" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_e8b3e678-a8a4-4591-98cf-c1f46680bce0" xlink:to="loc_us-gaap_ClassOfStockDomain_6647c5c8-3413-4259-8182-07bf69f04988" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesAPreferredStockMember_9916e844-b5a3-474f-8ee1-d98a50eaa284" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SeriesAPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_6647c5c8-3413-4259-8182-07bf69f04988" xlink:to="loc_us-gaap_SeriesAPreferredStockMember_9916e844-b5a3-474f-8ee1-d98a50eaa284" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_d4881925-7b2d-472b-92c5-2a56d660e441" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_6647c5c8-3413-4259-8182-07bf69f04988" xlink:to="loc_us-gaap_CommonClassAMember_d4881925-7b2d-472b-92c5-2a56d660e441" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_83ae93c2-b799-4f9f-8fc4-6966717b61a2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_6647c5c8-3413-4259-8182-07bf69f04988" xlink:to="loc_us-gaap_CommonClassBMember_83ae93c2-b799-4f9f-8fc4-6966717b61a2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_bf28c76c-0016-4e94-9f2a-f43f287c9777" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5b6261e6-b763-4c1e-bebc-ffb740e98d89" xlink:to="loc_us-gaap_AssetsAbstract_bf28c76c-0016-4e94-9f2a-f43f287c9777" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_1f714eec-95d9-4cdf-8e84-853d312928b9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bf28c76c-0016-4e94-9f2a-f43f287c9777" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_1f714eec-95d9-4cdf-8e84-853d312928b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarketableSecuritiesCurrent_e8f247ff-5d3b-4dd5-8c81-f3ac0443361c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MarketableSecuritiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bf28c76c-0016-4e94-9f2a-f43f287c9777" xlink:to="loc_us-gaap_MarketableSecuritiesCurrent_e8f247ff-5d3b-4dd5-8c81-f3ac0443361c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_02188888-9220-45f3-98fd-cea80b103e02" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bf28c76c-0016-4e94-9f2a-f43f287c9777" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_02188888-9220-45f3-98fd-cea80b103e02" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsCurrent_251efc8a-e105-4344-97c9-bc3225616d6e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bf28c76c-0016-4e94-9f2a-f43f287c9777" xlink:to="loc_us-gaap_OtherAssetsCurrent_251efc8a-e105-4344-97c9-bc3225616d6e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodFaithAndMarginDepositsWithBrokerDealers_7c3ab26e-2bc7-4de6-9c94-04eb73308e09" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodFaithAndMarginDepositsWithBrokerDealers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bf28c76c-0016-4e94-9f2a-f43f287c9777" xlink:to="loc_us-gaap_GoodFaithAndMarginDepositsWithBrokerDealers_7c3ab26e-2bc7-4de6-9c94-04eb73308e09" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_85b0d714-b16a-4645-93fb-9c0695f8de70" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bf28c76c-0016-4e94-9f2a-f43f287c9777" xlink:to="loc_us-gaap_AssetsCurrent_85b0d714-b16a-4645-93fb-9c0695f8de70" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_436f4e80-9793-4586-b17f-d29d5b37df1d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bf28c76c-0016-4e94-9f2a-f43f287c9777" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_436f4e80-9793-4586-b17f-d29d5b37df1d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIndefiniteLivedIntangibleAssets_b604047c-7ab4-4c1a-940a-ed91da1b9654" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherIndefiniteLivedIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bf28c76c-0016-4e94-9f2a-f43f287c9777" xlink:to="loc_us-gaap_OtherIndefiniteLivedIntangibleAssets_b604047c-7ab4-4c1a-940a-ed91da1b9654" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_83e6aedc-d7f1-4978-b9ad-ad75af4fb07a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bf28c76c-0016-4e94-9f2a-f43f287c9777" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_83e6aedc-d7f1-4978-b9ad-ad75af4fb07a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_0f1cd8a0-81e6-4b9c-ae4e-c55c32fb28bf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bf28c76c-0016-4e94-9f2a-f43f287c9777" xlink:to="loc_us-gaap_Goodwill_0f1cd8a0-81e6-4b9c-ae4e-c55c32fb28bf" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_835fb0fd-f7c1-4f97-9cff-eb4ff53650c9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bf28c76c-0016-4e94-9f2a-f43f287c9777" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_835fb0fd-f7c1-4f97-9cff-eb4ff53650c9" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_54eba915-f041-4163-b989-8c393a7fbacc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bf28c76c-0016-4e94-9f2a-f43f287c9777" xlink:to="loc_us-gaap_Assets_54eba915-f041-4163-b989-8c393a7fbacc" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_82adf0b7-b3ac-472c-b04a-55f1da62350a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5b6261e6-b763-4c1e-bebc-ffb740e98d89" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_82adf0b7-b3ac-472c-b04a-55f1da62350a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_99aaffea-ca00-404e-b3ad-29060b82d5b6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_82adf0b7-b3ac-472c-b04a-55f1da62350a" xlink:to="loc_us-gaap_AccountsPayableCurrent_99aaffea-ca00-404e-b3ad-29060b82d5b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_fa2325dc-99d6-4704-b910-c0e4a6d32701" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_82adf0b7-b3ac-472c-b04a-55f1da62350a" xlink:to="loc_us-gaap_ShortTermBorrowings_fa2325dc-99d6-4704-b910-c0e4a6d32701" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_37761a84-68de-4f5b-a5f0-fa7b85c6c02d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_82adf0b7-b3ac-472c-b04a-55f1da62350a" xlink:to="loc_us-gaap_OtherLiabilitiesCurrent_37761a84-68de-4f5b-a5f0-fa7b85c6c02d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_MarginDepositsAndGuarantyFundsLiabilitiesCurrent_e5beb49c-74cf-44de-8953-fb9b5dd76097" xlink:href="cme-20231231.xsd#cme_MarginDepositsAndGuarantyFundsLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_82adf0b7-b3ac-472c-b04a-55f1da62350a" xlink:to="loc_cme_MarginDepositsAndGuarantyFundsLiabilitiesCurrent_e5beb49c-74cf-44de-8953-fb9b5dd76097" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_d7b1daf5-1a9d-4bb3-96e6-53e87bafac22" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_82adf0b7-b3ac-472c-b04a-55f1da62350a" xlink:to="loc_us-gaap_LiabilitiesCurrent_d7b1daf5-1a9d-4bb3-96e6-53e87bafac22" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnsecuredLongTermDebt_a52757c0-2bc4-4031-a524-086ac5aa3f8f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnsecuredLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_82adf0b7-b3ac-472c-b04a-55f1da62350a" xlink:to="loc_us-gaap_UnsecuredLongTermDebt_a52757c0-2bc4-4031-a524-086ac5aa3f8f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_7ebf0e91-c31f-4a33-8891-be071e0d2b36" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_82adf0b7-b3ac-472c-b04a-55f1da62350a" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_7ebf0e91-c31f-4a33-8891-be071e0d2b36" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_8938df99-6115-4223-b863-e6070c0cd7b8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_82adf0b7-b3ac-472c-b04a-55f1da62350a" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_8938df99-6115-4223-b863-e6070c0cd7b8" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_af751f55-7d64-4909-aec0-025df270ea7f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_82adf0b7-b3ac-472c-b04a-55f1da62350a" xlink:to="loc_us-gaap_Liabilities_af751f55-7d64-4909-aec0-025df270ea7f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_e31d79b9-d166-4712-8b02-9b0c167226c4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_82adf0b7-b3ac-472c-b04a-55f1da62350a" xlink:to="loc_us-gaap_StockholdersEquityAbstract_e31d79b9-d166-4712-8b02-9b0c167226c4" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValue_c656fa5f-116f-40d1-ae6b-77a580b67878" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_e31d79b9-d166-4712-8b02-9b0c167226c4" xlink:to="loc_us-gaap_PreferredStockValue_c656fa5f-116f-40d1-ae6b-77a580b67878" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValueOutstanding_6d63c51f-1ca0-4596-aa26-9be6bf31a141" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockValueOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_e31d79b9-d166-4712-8b02-9b0c167226c4" xlink:to="loc_us-gaap_CommonStockValueOutstanding_6d63c51f-1ca0-4596-aa26-9be6bf31a141" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_34210806-04e5-4025-91a3-a10674c130c8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_e31d79b9-d166-4712-8b02-9b0c167226c4" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_34210806-04e5-4025-91a3-a10674c130c8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_e51a24e3-893f-49fe-be36-ac85c3245c11" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_e31d79b9-d166-4712-8b02-9b0c167226c4" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_e51a24e3-893f-49fe-be36-ac85c3245c11" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_1fcf4279-f169-4a0d-911c-b064cb1911a6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_e31d79b9-d166-4712-8b02-9b0c167226c4" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_1fcf4279-f169-4a0d-911c-b064cb1911a6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_6e0e7ab8-6350-4fa7-8c02-9e04fe4b0b26" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_e31d79b9-d166-4712-8b02-9b0c167226c4" xlink:to="loc_us-gaap_StockholdersEquity_6e0e7ab8-6350-4fa7-8c02-9e04fe4b0b26" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_ae950777-d04a-49fd-8479-8741583c707b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_82adf0b7-b3ac-472c-b04a-55f1da62350a" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_ae950777-d04a-49fd-8479-8741583c707b" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/CONSOLIDATEDSTATEMENTSOFINCOME" xlink:type="simple" xlink:href="cme-20231231.xsd#CONSOLIDATEDSTATEMENTSOFINCOME"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/CONSOLIDATEDSTATEMENTSOFINCOME" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_542a5d77-7129-4700-946a-bc0886721a1c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_dd3abf2e-8df8-4c73-8b0b-79756fa6d2c0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_542a5d77-7129-4700-946a-bc0886721a1c" xlink:to="loc_us-gaap_StatementTable_dd3abf2e-8df8-4c73-8b0b-79756fa6d2c0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_11201f48-87de-47d4-bf24-b72f30d07213" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_dd3abf2e-8df8-4c73-8b0b-79756fa6d2c0" xlink:to="loc_srt_ProductOrServiceAxis_11201f48-87de-47d4-bf24-b72f30d07213" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_11201f48-87de-47d4-bf24-b72f30d07213_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_11201f48-87de-47d4-bf24-b72f30d07213" xlink:to="loc_srt_ProductsAndServicesDomain_11201f48-87de-47d4-bf24-b72f30d07213_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_b01d515e-40e8-4b4f-ac45-b0cd5d66255d" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_11201f48-87de-47d4-bf24-b72f30d07213" xlink:to="loc_srt_ProductsAndServicesDomain_b01d515e-40e8-4b4f-ac45-b0cd5d66255d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClearingandtransactionfeesMember_186e823d-0ed4-403d-85ba-e23eb459de91" xlink:href="cme-20231231.xsd#cme_ClearingandtransactionfeesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_b01d515e-40e8-4b4f-ac45-b0cd5d66255d" xlink:to="loc_cme_ClearingandtransactionfeesMember_186e823d-0ed4-403d-85ba-e23eb459de91" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_MarketDataMember_2be05925-aae1-4f32-9822-84fe65fcbdcc" xlink:href="cme-20231231.xsd#cme_MarketDataMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_b01d515e-40e8-4b4f-ac45-b0cd5d66255d" xlink:to="loc_cme_MarketDataMember_2be05925-aae1-4f32-9822-84fe65fcbdcc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_OtherRevenueMember_2b027c03-b5d8-4ba4-8aa4-ec8b87382998" xlink:href="cme-20231231.xsd#cme_OtherRevenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_b01d515e-40e8-4b4f-ac45-b0cd5d66255d" xlink:to="loc_cme_OtherRevenueMember_2b027c03-b5d8-4ba4-8aa4-ec8b87382998" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementAbstract_c90ca801-d55f-4ead-86a7-5c2ff6c41baf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_542a5d77-7129-4700-946a-bc0886721a1c" xlink:to="loc_us-gaap_IncomeStatementAbstract_c90ca801-d55f-4ead-86a7-5c2ff6c41baf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_57916f90-6537-4c3d-989a-97d727435ada" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract_c90ca801-d55f-4ead-86a7-5c2ff6c41baf" xlink:to="loc_us-gaap_RevenuesAbstract_57916f90-6537-4c3d-989a-97d727435ada" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_85b5187b-00ce-49b0-b983-c067105561cb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_57916f90-6537-4c3d-989a-97d727435ada" xlink:to="loc_us-gaap_Revenues_85b5187b-00ce-49b0-b983-c067105561cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_fd0c74e0-d4c7-4393-a0b6-2260ca250b30" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CostsAndExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract_c90ca801-d55f-4ead-86a7-5c2ff6c41baf" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_fd0c74e0-d4c7-4393-a0b6-2260ca250b30" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LaborAndRelatedExpense_c937bf19-ff71-46b0-a35d-cc5ff198f5a2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LaborAndRelatedExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_fd0c74e0-d4c7-4393-a0b6-2260ca250b30" xlink:to="loc_us-gaap_LaborAndRelatedExpense_c937bf19-ff71-46b0-a35d-cc5ff198f5a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InformationTechnologyAndDataProcessing_6b9a465c-deff-41c8-a126-f08ff469b6a2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InformationTechnologyAndDataProcessing"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_fd0c74e0-d4c7-4393-a0b6-2260ca250b30" xlink:to="loc_us-gaap_InformationTechnologyAndDataProcessing_6b9a465c-deff-41c8-a126-f08ff469b6a2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfessionalFees_54c7c313-d55e-4309-aecc-f8287639e28f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProfessionalFees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_fd0c74e0-d4c7-4393-a0b6-2260ca250b30" xlink:to="loc_us-gaap_ProfessionalFees_54c7c313-d55e-4309-aecc-f8287639e28f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_e5800926-8577-4f36-8a58-8b731921c4d4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_fd0c74e0-d4c7-4393-a0b6-2260ca250b30" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_e5800926-8577-4f36-8a58-8b731921c4d4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization_879cd249-6193-4a84-a292-631c8c6aed03" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_fd0c74e0-d4c7-4393-a0b6-2260ca250b30" xlink:to="loc_us-gaap_DepreciationAndAmortization_879cd249-6193-4a84-a292-631c8c6aed03" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_LicensingFees_1eb88d31-2ffa-4cac-bb53-5a879877736f" xlink:href="cme-20231231.xsd#cme_LicensingFees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_fd0c74e0-d4c7-4393-a0b6-2260ca250b30" xlink:to="loc_cme_LicensingFees_1eb88d31-2ffa-4cac-bb53-5a879877736f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCostAndExpenseOperating_af07f897-6c0c-4876-8f9f-a10df0346d88" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherCostAndExpenseOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_fd0c74e0-d4c7-4393-a0b6-2260ca250b30" xlink:to="loc_us-gaap_OtherCostAndExpenseOperating_af07f897-6c0c-4876-8f9f-a10df0346d88" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_0ce5d618-b37f-48a0-8e14-a1e13bf20b53" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_fd0c74e0-d4c7-4393-a0b6-2260ca250b30" xlink:to="loc_us-gaap_CostsAndExpenses_0ce5d618-b37f-48a0-8e14-a1e13bf20b53" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_e08f439c-230c-47bc-9a6f-7f802858bed5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract_c90ca801-d55f-4ead-86a7-5c2ff6c41baf" xlink:to="loc_us-gaap_OperatingIncomeLoss_e08f439c-230c-47bc-9a6f-7f802858bed5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract_2d63637b-53c1-4308-b430-35b78549c481" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NonoperatingIncomeExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract_c90ca801-d55f-4ead-86a7-5c2ff6c41baf" xlink:to="loc_us-gaap_NonoperatingIncomeExpenseAbstract_2d63637b-53c1-4308-b430-35b78549c481" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeNonoperating_2f077507-70fd-4053-8f5c-6404f49f29f0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InvestmentIncomeNonoperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_2d63637b-53c1-4308-b430-35b78549c481" xlink:to="loc_us-gaap_InvestmentIncomeNonoperating_2f077507-70fd-4053-8f5c-6404f49f29f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndDebtExpense_c1ffa86e-3be8-4ad7-ba4c-f1140af1ebbb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InterestAndDebtExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_2d63637b-53c1-4308-b430-35b78549c481" xlink:to="loc_us-gaap_InterestAndDebtExpense_c1ffa86e-3be8-4ad7-ba4c-f1140af1ebbb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_cd4260ac-91c1-42ca-b8c6-e7a064f3077a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_2d63637b-53c1-4308-b430-35b78549c481" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_cd4260ac-91c1-42ca-b8c6-e7a064f3077a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_1d15e87e-d93c-4a5c-af77-f9eb3e630fe5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_2d63637b-53c1-4308-b430-35b78549c481" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_1d15e87e-d93c-4a5c-af77-f9eb3e630fe5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_ee762eea-7247-4899-a43c-ae05dc69200a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_2d63637b-53c1-4308-b430-35b78549c481" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_ee762eea-7247-4899-a43c-ae05dc69200a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossIncludingPortionAttributableToNoncontrollingInterest_64a41be9-f21d-42c5-8371-a4a54742112a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeLossIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract_c90ca801-d55f-4ead-86a7-5c2ff6c41baf" xlink:to="loc_us-gaap_IncomeLossIncludingPortionAttributableToNoncontrollingInterest_64a41be9-f21d-42c5-8371-a4a54742112a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_fa68def9-2aa3-41aa-80fc-f8876be6ed41" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract_c90ca801-d55f-4ead-86a7-5c2ff6c41baf" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_fa68def9-2aa3-41aa-80fc-f8876be6ed41" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest_826c013e-14a2-4b6c-b529-4791d6f1ccb3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract_c90ca801-d55f-4ead-86a7-5c2ff6c41baf" xlink:to="loc_us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest_826c013e-14a2-4b6c-b529-4791d6f1ccb3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_372a4749-cb39-401a-94ec-8b36526f2da4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract_c90ca801-d55f-4ead-86a7-5c2ff6c41baf" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_372a4749-cb39-401a-94ec-8b36526f2da4" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_9a2ff4be-1b8b-479f-aa18-22fdaf353870" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract_c90ca801-d55f-4ead-86a7-5c2ff6c41baf" xlink:to="loc_us-gaap_NetIncomeLoss_9a2ff4be-1b8b-479f-aa18-22fdaf353870" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_2ef7e939-4ee4-4bf8-ae0c-f68bff8df95f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract_c90ca801-d55f-4ead-86a7-5c2ff6c41baf" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_2ef7e939-4ee4-4bf8-ae0c-f68bff8df95f" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_5b732b3f-3556-481b-bf97-991557de6397" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract_c90ca801-d55f-4ead-86a7-5c2ff6c41baf" xlink:to="loc_us-gaap_EarningsPerShareAbstract_5b732b3f-3556-481b-bf97-991557de6397" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_1dc8482e-61bb-4196-852f-f1fcb4c33b85" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_5b732b3f-3556-481b-bf97-991557de6397" xlink:to="loc_us-gaap_EarningsPerShareBasic_1dc8482e-61bb-4196-852f-f1fcb4c33b85" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_5304a997-2156-4b6c-be6d-317d18921c23" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_5b732b3f-3556-481b-bf97-991557de6397" xlink:to="loc_us-gaap_EarningsPerShareDiluted_5304a997-2156-4b6c-be6d-317d18921c23" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019584a8-c2a2-41e2-b2d3-9cf1e895c38b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract_c90ca801-d55f-4ead-86a7-5c2ff6c41baf" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019584a8-c2a2-41e2-b2d3-9cf1e895c38b" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_8dc69b8f-dba9-4891-a1b0-dc4f7ec020eb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019584a8-c2a2-41e2-b2d3-9cf1e895c38b" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_8dc69b8f-dba9-4891-a1b0-dc4f7ec020eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_f298bec8-0488-4768-afcc-c3f52da1a2c9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_019584a8-c2a2-41e2-b2d3-9cf1e895c38b" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_f298bec8-0488-4768-afcc-c3f52da1a2c9" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME" xlink:type="simple" xlink:href="cme-20231231.xsd#CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_1ddbbf7c-3c51-48d2-9f97-b60d381559cd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_StatementTable_1ddbbf7c-3c51-48d2-9f97-b60d381559cd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_1020fe02-a4cf-4633-9ad1-f7aad09488ad" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1ddbbf7c-3c51-48d2-9f97-b60d381559cd" xlink:to="loc_srt_StatementScenarioAxis_1020fe02-a4cf-4633-9ad1-f7aad09488ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_1020fe02-a4cf-4633-9ad1-f7aad09488ad_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_1020fe02-a4cf-4633-9ad1-f7aad09488ad" xlink:to="loc_srt_ScenarioUnspecifiedDomain_1020fe02-a4cf-4633-9ad1-f7aad09488ad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_ad4d424d-c93b-4254-a5be-0eec2a8a0fd7" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_1020fe02-a4cf-4633-9ad1-f7aad09488ad" xlink:to="loc_srt_ScenarioUnspecifiedDomain_ad4d424d-c93b-4254-a5be-0eec2a8a0fd7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_11019653-5f54-4721-bd3d-0e01910e6511" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_ProfitLoss_11019653-5f54-4721-bd3d-0e01910e6511" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax_eb23dd0e-e34c-4cf3-87bc-da447d171849" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax_eb23dd0e-e34c-4cf3-87bc-da447d171849" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax_724b1abc-04be-4113-ade4-e48dc1d1af9c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax_724b1abc-04be-4113-ade4-e48dc1d1af9c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax_96d09cfb-0b69-4db7-9ce0-a77e3c5bd730" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax_96d09cfb-0b69-4db7-9ce0-a77e3c5bd730" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_7bf2aa66-e610-4526-992b-46f4f325d597" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_7bf2aa66-e610-4526-992b-46f4f325d597" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax_0e1a6179-721e-4043-a0a2-89c68275b9f2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax_0e1a6179-721e-4043-a0a2-89c68275b9f2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax_57dd429e-d1fb-4008-b67a-f0e960f83118" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax_57dd429e-d1fb-4008-b67a-f0e960f83118" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax_7dfeeac5-ecca-483d-a5e5-a71bcbb892cf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax_7dfeeac5-ecca-483d-a5e5-a71bcbb892cf" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_8a483961-d561-4b5d-b154-04e43c8e2760" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_8a483961-d561-4b5d-b154-04e43c8e2760" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_a8973f38-bddb-461a-aec1-49af0898f274" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_a8973f38-bddb-461a-aec1-49af0898f274" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationTax_3931bb63-520a-4813-bdb4-de970e16996c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationTax_3931bb63-520a-4813-bdb4-de970e16996c" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax_b4ab77b2-45f3-4ae4-b612-f25ec07bd1ad" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax_b4ab77b2-45f3-4ae4-b612-f25ec07bd1ad" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax_ffc6d11d-017a-4f27-9a41-6ce1c87b2af3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax_ffc6d11d-017a-4f27-9a41-6ce1c87b2af3" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_OtherComprehensiveIncomeLossForeignCurrentyTranslationReclassification_ddf63798-8d3a-4ad7-93fb-a641dd44e17e" xlink:href="cme-20231231.xsd#cme_OtherComprehensiveIncomeLossForeignCurrentyTranslationReclassification"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_cme_OtherComprehensiveIncomeLossForeignCurrentyTranslationReclassification_ddf63798-8d3a-4ad7-93fb-a641dd44e17e" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_1cf0012b-af7f-4ccc-aec8-694ce33077f8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax_1cf0012b-af7f-4ccc-aec8-694ce33077f8" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_e23526a5-5592-4fb2-8694-010cb3d91f6c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_e23526a5-5592-4fb2-8694-010cb3d91f6c" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_0050761a-77e6-4eaf-b771-301a456895d8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_0050761a-77e6-4eaf-b771-301a456895d8" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest_d023c003-393c-41bc-b399-9c0c3985c884" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest_d023c003-393c-41bc-b399-9c0c3985c884" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_ca2fe28c-f7bf-46f7-898d-4ff6969d9b2d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_42258f2d-0444-4088-8302-da02aab309cf" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_ca2fe28c-f7bf-46f7-898d-4ff6969d9b2d" xlink:type="arc" order="18"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/CONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY" xlink:type="simple" xlink:href="cme-20231231.xsd#CONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/CONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_9e8cfd08-434d-41e2-9dfe-ff467043abd2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_236b06e6-2cda-418c-808c-189ef7433d68" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_9e8cfd08-434d-41e2-9dfe-ff467043abd2" xlink:to="loc_us-gaap_StatementTable_236b06e6-2cda-418c-808c-189ef7433d68" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_e8e20164-1033-4e54-ab88-b642b5bc849e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_236b06e6-2cda-418c-808c-189ef7433d68" xlink:to="loc_us-gaap_StatementClassOfStockAxis_e8e20164-1033-4e54-ab88-b642b5bc849e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_e8e20164-1033-4e54-ab88-b642b5bc849e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_e8e20164-1033-4e54-ab88-b642b5bc849e" xlink:to="loc_us-gaap_ClassOfStockDomain_e8e20164-1033-4e54-ab88-b642b5bc849e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_da55b957-d66b-4fe8-a3a8-151df2fac93d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_e8e20164-1033-4e54-ab88-b642b5bc849e" xlink:to="loc_us-gaap_ClassOfStockDomain_da55b957-d66b-4fe8-a3a8-151df2fac93d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesAPreferredStockMember_628b0e00-69c8-4e0b-a668-3c6b694f0dd9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SeriesAPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_da55b957-d66b-4fe8-a3a8-151df2fac93d" xlink:to="loc_us-gaap_SeriesAPreferredStockMember_628b0e00-69c8-4e0b-a668-3c6b694f0dd9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_80865c68-1bfc-4ac6-a4dc-cf39892e6028" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_da55b957-d66b-4fe8-a3a8-151df2fac93d" xlink:to="loc_us-gaap_CommonClassAMember_80865c68-1bfc-4ac6-a4dc-cf39892e6028" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_b01b4fc1-3fc8-4c63-9149-95f8443212ca" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_da55b957-d66b-4fe8-a3a8-151df2fac93d" xlink:to="loc_us-gaap_CommonClassBMember_b01b4fc1-3fc8-4c63-9149-95f8443212ca" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertiblePreferredStockMember_01c925ee-8c04-44a2-96d0-3f9c9e712f45" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_da55b957-d66b-4fe8-a3a8-151df2fac93d" xlink:to="loc_us-gaap_ConvertiblePreferredStockMember_01c925ee-8c04-44a2-96d0-3f9c9e712f45" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_da6c21a1-b9f6-4aaf-9358-244fb5a62749" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_236b06e6-2cda-418c-808c-189ef7433d68" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_da6c21a1-b9f6-4aaf-9358-244fb5a62749" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_da6c21a1-b9f6-4aaf-9358-244fb5a62749_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_da6c21a1-b9f6-4aaf-9358-244fb5a62749" xlink:to="loc_us-gaap_EquityComponentDomain_da6c21a1-b9f6-4aaf-9358-244fb5a62749_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_7ee69dc4-8aa4-4ba3-a670-dc80223a4b75" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_da6c21a1-b9f6-4aaf-9358-244fb5a62749" xlink:to="loc_us-gaap_EquityComponentDomain_7ee69dc4-8aa4-4ba3-a670-dc80223a4b75" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember_a276313e-9335-4cbc-99d0-5db06ea3b82f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_7ee69dc4-8aa4-4ba3-a670-dc80223a4b75" xlink:to="loc_us-gaap_CommonStockIncludingAdditionalPaidInCapitalMember_a276313e-9335-4cbc-99d0-5db06ea3b82f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParentMember_6cabdd92-ce36-479e-a0c9-cec1d29949a7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_7ee69dc4-8aa4-4ba3-a670-dc80223a4b75" xlink:to="loc_us-gaap_ParentMember_6cabdd92-ce36-479e-a0c9-cec1d29949a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_e70c6b18-12c9-465d-bce0-b7808792b894" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_7ee69dc4-8aa4-4ba3-a670-dc80223a4b75" xlink:to="loc_us-gaap_RetainedEarningsMember_e70c6b18-12c9-465d-bce0-b7808792b894" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_dc1a3f53-b374-4890-935f-76da179245a8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_7ee69dc4-8aa4-4ba3-a670-dc80223a4b75" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_dc1a3f53-b374-4890-935f-76da179245a8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_c1ca50aa-d992-4472-8abc-43ecb50bce9d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_7ee69dc4-8aa4-4ba3-a670-dc80223a4b75" xlink:to="loc_us-gaap_NoncontrollingInterestMember_c1ca50aa-d992-4472-8abc-43ecb50bce9d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9e8cfd08-434d-41e2-9dfe-ff467043abd2" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_753e2114-8746-4d85-a366-842f368b07f2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_StockholdersEquity_753e2114-8746-4d85-a366-842f368b07f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonredeemableNoncontrollingInterest_0b5ac50a-418d-45bd-afe2-ea28df43b6f0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NonredeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_NonredeemableNoncontrollingInterest_0b5ac50a-418d-45bd-afe2-ea28df43b6f0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_f61365d5-da66-4cee-8306-ae8208bf7032" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_f61365d5-da66-4cee-8306-ae8208bf7032" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_cbd9d1a7-a3b7-4788-83c0-5b8bf771bf85" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_cbd9d1a7-a3b7-4788-83c0-5b8bf771bf85" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_59487981-1d0d-40a5-96b0-01d56345c3cb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_NetIncomeLoss_59487981-1d0d-40a5-96b0-01d56345c3cb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest_e39ea188-4136-41a4-b3a7-f594beaf075b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest_e39ea188-4136-41a4-b3a7-f594beaf075b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest_944ba300-ebc6-48ae-a910-cb0d92bcbcca" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest_944ba300-ebc6-48ae-a910-cb0d92bcbcca" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_600de946-edd6-4760-97ba-73cd0c63342c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_600de946-edd6-4760-97ba-73cd0c63342c" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCash_346cc02c-a5e5-4344-a6cd-a2fb80f77dd8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DividendsCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_DividendsCash_346cc02c-a5e5-4344-a6cd-a2fb80f77dd8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockConsiderationReceivedOnTransaction_cab56c41-f107-4eb1-a858-760f35ee5332" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleOfStockConsiderationReceivedOnTransaction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_SaleOfStockConsiderationReceivedOnTransaction_cab56c41-f107-4eb1-a858-760f35ee5332" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesIssued_59862fcb-4dd8-484a-834b-0ffaa8194b3d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_PreferredStockSharesIssued_59862fcb-4dd8-484a-834b-0ffaa8194b3d" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityOther_107f9dd6-7657-4fbd-9103-d0690d31e2c4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_StockholdersEquityOther_107f9dd6-7657-4fbd-9103-d0690d31e2c4" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromRedemptions_393636a5-074b-4041-9e95-5a3af1611e1f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MinorityInterestDecreaseFromRedemptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromRedemptions_393636a5-074b-4041-9e95-5a3af1611e1f" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_adf2f328-a8c8-45f5-a6b6-b14e7d551e18" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_adf2f328-a8c8-45f5-a6b6-b14e7d551e18" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_47ac7c55-0d4b-48ff-888c-6a9fa23e48e5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_47ac7c55-0d4b-48ff-888c-6a9fa23e48e5" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross_bb84292a-3cbb-432b-b115-515028473025" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross_bb84292a-3cbb-432b-b115-515028473025" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_eb0d0e09-2c3a-4ed8-b464-66fe7b427b97" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_eb0d0e09-2c3a-4ed8-b464-66fe7b427b97" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_75ae92b8-f6c0-4d7c-843d-c8348afc6405" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_75ae92b8-f6c0-4d7c-843d-c8348afc6405" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueIssuedForServices_fa8c114f-0b1f-44f5-91c4-f70ca2e8e391" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueIssuedForServices_fa8c114f-0b1f-44f5-91c4-f70ca2e8e391" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_d28f6d0c-d640-4c78-9cf9-0cb01e71a1d2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_d28f6d0c-d640-4c78-9cf9-0cb01e71a1d2" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_883f75ca-58ab-469b-8cb5-e2f8960cb596" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_883f75ca-58ab-469b-8cb5-e2f8960cb596" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation_9c28f6f3-1806-4136-9b4e-f925299cef9a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation_9c28f6f3-1806-4136-9b4e-f925299cef9a" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_89afec8b-ef68-4459-a6ec-b5f2c0346201" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonredeemableNoncontrollingInterest_bc104e57-c6e8-4442-b9ef-b96ac5f3d371" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NonredeemableNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_1115f245-618d-4085-ae35-7fbd72deccb8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_02e5db68-a661-44e3-9706-02b7aaee82a0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestPeriodIncreaseDecrease_e5715a95-e5cd-43c0-9353-c25e51411f2f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MinorityInterestPeriodIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_9fc02502-8fd1-4bbd-a4c3-43dd2b8ae11c" xlink:to="loc_us-gaap_MinorityInterestPeriodIncreaseDecrease_e5715a95-e5cd-43c0-9353-c25e51411f2f" xlink:type="arc" order="27"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS" xlink:type="simple" xlink:href="cme-20231231.xsd#CONSOLIDATEDSTATEMENTSOFCASHFLOWS"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_31f53a84-8e3f-4c7f-9aa0-c5f91022af6e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_dd01ef98-9bbd-4774-8e9c-09f8b2163d9b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_31f53a84-8e3f-4c7f-9aa0-c5f91022af6e" xlink:to="loc_us-gaap_StatementTable_dd01ef98-9bbd-4774-8e9c-09f8b2163d9b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_a6d740a9-a131-4117-bd43-337153796058" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_dd01ef98-9bbd-4774-8e9c-09f8b2163d9b" xlink:to="loc_srt_StatementScenarioAxis_a6d740a9-a131-4117-bd43-337153796058" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_a6d740a9-a131-4117-bd43-337153796058_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_a6d740a9-a131-4117-bd43-337153796058" xlink:to="loc_srt_ScenarioUnspecifiedDomain_a6d740a9-a131-4117-bd43-337153796058_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_f301f74e-a6a5-4ae5-ac6d-e808cd9e2673" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_a6d740a9-a131-4117-bd43-337153796058" xlink:to="loc_srt_ScenarioUnspecifiedDomain_f301f74e-a6a5-4ae5-ac6d-e808cd9e2673" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_c32a05f0-745e-47f0-9bbf-ff37258d481c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31f53a84-8e3f-4c7f-9aa0-c5f91022af6e" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_c32a05f0-745e-47f0-9bbf-ff37258d481c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_c3ecf686-90b1-4b61-97fa-edf4ee9c812a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_c32a05f0-745e-47f0-9bbf-ff37258d481c" xlink:to="loc_us-gaap_ProfitLoss_c3ecf686-90b1-4b61-97fa-edf4ee9c812a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_95dd4c43-384d-48d6-bbb9-4cfd52419e26" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_c32a05f0-745e-47f0-9bbf-ff37258d481c" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_95dd4c43-384d-48d6-bbb9-4cfd52419e26" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_f5eb1d1c-b7b5-4b06-9633-ac8a95936108" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_95dd4c43-384d-48d6-bbb9-4cfd52419e26" xlink:to="loc_us-gaap_ShareBasedCompensation_f5eb1d1c-b7b5-4b06-9633-ac8a95936108" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_3e6b8931-5776-4dde-8ae9-ebfbbdff221f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_95dd4c43-384d-48d6-bbb9-4cfd52419e26" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_3e6b8931-5776-4dde-8ae9-ebfbbdff221f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization_0169bbe4-7972-4080-8659-6bbab064fc55" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_95dd4c43-384d-48d6-bbb9-4cfd52419e26" xlink:to="loc_us-gaap_DepreciationAndAmortization_0169bbe4-7972-4080-8659-6bbab064fc55" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets_e2d6280f-13d1-4d9c-aec5-45849cb97a31" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GainLossOnDispositionOfAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_95dd4c43-384d-48d6-bbb9-4cfd52419e26" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets_e2d6280f-13d1-4d9c-aec5-45849cb97a31" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeconsolidationGainOrLossAmount_beeb9ace-db11-4a5b-b8ca-b56e9aed8cd8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeconsolidationGainOrLossAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_95dd4c43-384d-48d6-bbb9-4cfd52419e26" xlink:to="loc_us-gaap_DeconsolidationGainOrLossAmount_beeb9ace-db11-4a5b-b8ca-b56e9aed8cd8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnInvestments_c9b17ee4-906e-4293-ab31-6763e1a13484" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GainLossOnInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_95dd4c43-384d-48d6-bbb9-4cfd52419e26" xlink:to="loc_us-gaap_GainLossOnInvestments_c9b17ee4-906e-4293-ab31-6763e1a13484" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_b597602b-4a3b-4a91-9001-19d8c652aedd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_95dd4c43-384d-48d6-bbb9-4cfd52419e26" xlink:to="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_b597602b-4a3b-4a91-9001-19d8c652aedd" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_7c61fde9-f7c8-4d52-9b99-8ced8b822e49" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_95dd4c43-384d-48d6-bbb9-4cfd52419e26" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_7c61fde9-f7c8-4d52-9b99-8ced8b822e49" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_5a9c7a54-ce4e-4945-805c-a8ffbd042260" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_7c61fde9-f7c8-4d52-9b99-8ced8b822e49" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_5a9c7a54-ce4e-4945-805c-a8ffbd042260" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_5995ff2e-fb87-4bce-af86-578e8305c172" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_7c61fde9-f7c8-4d52-9b99-8ced8b822e49" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_5995ff2e-fb87-4bce-af86-578e8305c172" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_98bd1972-2fd0-4bce-ae57-ad7d0b956e0c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_7c61fde9-f7c8-4d52-9b99-8ced8b822e49" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_98bd1972-2fd0-4bce-ae57-ad7d0b956e0c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_60be667e-0d4c-4f9a-b7e5-61e49b7ae557" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_7c61fde9-f7c8-4d52-9b99-8ced8b822e49" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_60be667e-0d4c-4f9a-b7e5-61e49b7ae557" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_9291fa67-31d9-4c4f-ac3e-a5fd2747a4c7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_7c61fde9-f7c8-4d52-9b99-8ced8b822e49" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_9291fa67-31d9-4c4f-ac3e-a5fd2747a4c7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherAccruedLiabilities_09431018-867b-41d1-a24f-6b2429d9dc5c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInOtherAccruedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_7c61fde9-f7c8-4d52-9b99-8ced8b822e49" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherAccruedLiabilities_09431018-867b-41d1-a24f-6b2429d9dc5c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_2aecad35-ff7f-45f6-b8ea-260dde0dd452" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInOtherOperatingLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_7c61fde9-f7c8-4d52-9b99-8ced8b822e49" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_2aecad35-ff7f-45f6-b8ea-260dde0dd452" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense_197e7044-391c-4e04-b317-4288edeba4d9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherNoncashIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_7c61fde9-f7c8-4d52-9b99-8ced8b822e49" xlink:to="loc_us-gaap_OtherNoncashIncomeExpense_197e7044-391c-4e04-b317-4288edeba4d9" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_235cef32-c373-4b76-9ca4-c7dec9f8c8b5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_c32a05f0-745e-47f0-9bbf-ff37258d481c" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_235cef32-c373-4b76-9ca4-c7dec9f8c8b5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_25e19720-6b9a-4b69-a710-463b8dfb82b4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31f53a84-8e3f-4c7f-9aa0-c5f91022af6e" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_25e19720-6b9a-4b69-a710-463b8dfb82b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_3db5fba4-5ac9-4fcb-adcb-b1d6deb54057" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_25e19720-6b9a-4b69-a710-463b8dfb82b4" xlink:to="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_3db5fba4-5ac9-4fcb-adcb-b1d6deb54057" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_fb8b602e-b586-4b1e-b86e-6e9c4f1a5699" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_25e19720-6b9a-4b69-a710-463b8dfb82b4" xlink:to="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_fb8b602e-b586-4b1e-b86e-6e9c4f1a5699" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_f2594aed-5424-48d8-91e1-244dda377564" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_25e19720-6b9a-4b69-a710-463b8dfb82b4" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_f2594aed-5424-48d8-91e1-244dda377564" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireOtherInvestments_86106048-0d66-4aca-9463-d062f03f16e0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsToAcquireOtherInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_25e19720-6b9a-4b69-a710-463b8dfb82b4" xlink:to="loc_us-gaap_PaymentsToAcquireOtherInvestments_86106048-0d66-4aca-9463-d062f03f16e0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfOtherInvestments_113fe2c7-1173-4669-9b89-64ab88453acb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromSaleOfOtherInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_25e19720-6b9a-4b69-a710-463b8dfb82b4" xlink:to="loc_us-gaap_ProceedsFromSaleOfOtherInvestments_113fe2c7-1173-4669-9b89-64ab88453acb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_PaymentForAcquisitionOfSubsidiarysInterestsFromTheNonControllingInterest_75d67123-ca75-4dbe-b319-411b34e1d7ce" xlink:href="cme-20231231.xsd#cme_PaymentForAcquisitionOfSubsidiarysInterestsFromTheNonControllingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_25e19720-6b9a-4b69-a710-463b8dfb82b4" xlink:to="loc_cme_PaymentForAcquisitionOfSubsidiarysInterestsFromTheNonControllingInterest_75d67123-ca75-4dbe-b319-411b34e1d7ce" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_dc18e979-588d-4b3e-81e9-74318defcb22" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_25e19720-6b9a-4b69-a710-463b8dfb82b4" xlink:to="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_dc18e979-588d-4b3e-81e9-74318defcb22" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfBusinessesAndInterestsInAffiliates_5e6982a7-80e0-4e83-81da-148deaa0690a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromDivestitureOfBusinessesAndInterestsInAffiliates"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_25e19720-6b9a-4b69-a710-463b8dfb82b4" xlink:to="loc_us-gaap_ProceedsFromDivestitureOfBusinessesAndInterestsInAffiliates_5e6982a7-80e0-4e83-81da-148deaa0690a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireInterestInJointVenture_fecd738f-1447-4040-ae24-7e9aaef6c0fc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsToAcquireInterestInJointVenture"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_25e19720-6b9a-4b69-a710-463b8dfb82b4" xlink:to="loc_us-gaap_PaymentsToAcquireInterestInJointVenture_fecd738f-1447-4040-ae24-7e9aaef6c0fc" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_04839829-b770-4512-9e2f-46ed950a9a43" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_25e19720-6b9a-4b69-a710-463b8dfb82b4" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_04839829-b770-4512-9e2f-46ed950a9a43" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b1b01d1d-ffb9-47fa-9073-c0bca6b12ab1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31f53a84-8e3f-4c7f-9aa0-c5f91022af6e" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b1b01d1d-ffb9-47fa-9073-c0bca6b12ab1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDebtNetOfIssuanceCosts_ba96a8c8-bf64-4d32-a530-f4869d1bb3ba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromDebtNetOfIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b1b01d1d-ffb9-47fa-9073-c0bca6b12ab1" xlink:to="loc_us-gaap_ProceedsFromDebtNetOfIssuanceCosts_ba96a8c8-bf64-4d32-a530-f4869d1bb3ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfOtherDebt_0f5c0792-ee0a-4204-b0b0-e762de48af5e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RepaymentsOfOtherDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b1b01d1d-ffb9-47fa-9073-c0bca6b12ab1" xlink:to="loc_us-gaap_RepaymentsOfOtherDebt_0f5c0792-ee0a-4204-b0b0-e762de48af5e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfPreferredStockAndPreferenceStock_c63b0d24-fb56-4969-b5e1-0dcfc7f04e89" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromIssuanceOfPreferredStockAndPreferenceStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b1b01d1d-ffb9-47fa-9073-c0bca6b12ab1" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfPreferredStockAndPreferenceStock_c63b0d24-fb56-4969-b5e1-0dcfc7f04e89" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividends_1157766c-3974-4673-aa8c-92ab77390bc2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsOfDividends"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b1b01d1d-ffb9-47fa-9073-c0bca6b12ab1" xlink:to="loc_us-gaap_PaymentsOfDividends_1157766c-3974-4673-aa8c-92ab77390bc2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ChangeInPerformanceBondAndGuarantyFundContributions_79048fd5-f38b-459f-9d05-1c3be081a774" xlink:href="cme-20231231.xsd#cme_ChangeInPerformanceBondAndGuarantyFundContributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b1b01d1d-ffb9-47fa-9073-c0bca6b12ab1" xlink:to="loc_cme_ChangeInPerformanceBondAndGuarantyFundContributions_79048fd5-f38b-459f-9d05-1c3be081a774" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_46676a2b-1ac5-44c8-8acf-2b9eccb3afef" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b1b01d1d-ffb9-47fa-9073-c0bca6b12ab1" xlink:to="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_46676a2b-1ac5-44c8-8acf-2b9eccb3afef" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_f0b9c5ae-84f8-41b8-998b-bb0c005aa26d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromPaymentsForOtherFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b1b01d1d-ffb9-47fa-9073-c0bca6b12ab1" xlink:to="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_f0b9c5ae-84f8-41b8-998b-bb0c005aa26d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_b607a406-7571-410b-9458-7850616f3c15" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b1b01d1d-ffb9-47fa-9073-c0bca6b12ab1" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_b607a406-7571-410b-9458-7850616f3c15" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_369c8825-e187-4ffb-b51e-d226a6325de4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31f53a84-8e3f-4c7f-9aa0-c5f91022af6e" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_369c8825-e187-4ffb-b51e-d226a6325de4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_eebef7e7-f208-47cf-a1fc-99ecbbc755d9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31f53a84-8e3f-4c7f-9aa0-c5f91022af6e" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_eebef7e7-f208-47cf-a1fc-99ecbbc755d9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_5de81775-8e11-47e7-81ee-300f71ae1242" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract_9f823523-e48b-4562-87e9-31448860540b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SupplementalCashFlowInformationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31f53a84-8e3f-4c7f-9aa0-c5f91022af6e" xlink:to="loc_us-gaap_SupplementalCashFlowInformationAbstract_9f823523-e48b-4562-87e9-31448860540b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_2fc2c3d8-8ea3-4df7-95af-98d627bb3ccd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_9f823523-e48b-4562-87e9-31448860540b" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_2fc2c3d8-8ea3-4df7-95af-98d627bb3ccd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_3ed2634d-3f79-4ed4-aac5-8cb3f87b3c60" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_9f823523-e48b-4562-87e9-31448860540b" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_3ed2634d-3f79-4ed4-aac5-8cb3f87b3c60" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsNoncurrent_6c232878-8885-451a-9bd0-09564fd5b070" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedCashAndCashEquivalentsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_9f823523-e48b-4562-87e9-31448860540b" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsNoncurrent_6c232878-8885-451a-9bd0-09564fd5b070" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodFaithAndMarginDepositsWithBrokerDealers_0930969c-802c-4a0b-89be-0c61706afb50" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodFaithAndMarginDepositsWithBrokerDealers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_9f823523-e48b-4562-87e9-31448860540b" xlink:to="loc_us-gaap_GoodFaithAndMarginDepositsWithBrokerDealers_0930969c-802c-4a0b-89be-0c61706afb50" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesPaid_8fc1a752-3cd5-4e3f-bdf2-edaab7528c1a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxesPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_9f823523-e48b-4562-87e9-31448860540b" xlink:to="loc_us-gaap_IncomeTaxesPaid_8fc1a752-3cd5-4e3f-bdf2-edaab7528c1a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPaidNet_50da9d96-4ffb-4f54-93f1-97d3bdb33ab6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InterestPaidNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_9f823523-e48b-4562-87e9-31448860540b" xlink:to="loc_us-gaap_InterestPaidNet_50da9d96-4ffb-4f54-93f1-97d3bdb33ab6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_Dividendsdeclared_31eea755-b307-4d8b-b46b-c98fecbb8df2" xlink:href="cme-20231231.xsd#cme_Dividendsdeclared"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_9f823523-e48b-4562-87e9-31448860540b" xlink:to="loc_cme_Dividendsdeclared_31eea755-b307-4d8b-b46b-c98fecbb8df2" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/CONSOLIDATEDBALANCESHEETSParentheticals" xlink:type="simple" xlink:href="cme-20231231.xsd#CONSOLIDATEDBALANCESHEETSParentheticals"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/CONSOLIDATEDBALANCESHEETSParentheticals" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedBalanceSheetStatementsCaptionsLineItems_372982c5-de9a-4946-9d1c-7645c3b7ecf7" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CondensedBalanceSheetStatementsCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedBalanceSheetStatementTable_0bbcb02f-ae9f-4e4c-a029-c0bf08e0a14a" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_CondensedBalanceSheetStatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedBalanceSheetStatementsCaptionsLineItems_372982c5-de9a-4946-9d1c-7645c3b7ecf7" xlink:to="loc_srt_CondensedBalanceSheetStatementTable_0bbcb02f-ae9f-4e4c-a029-c0bf08e0a14a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_76c8695f-7b50-45b8-a4c4-4d384a7901c9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_CondensedBalanceSheetStatementTable_0bbcb02f-ae9f-4e4c-a029-c0bf08e0a14a" xlink:to="loc_us-gaap_StatementClassOfStockAxis_76c8695f-7b50-45b8-a4c4-4d384a7901c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_76c8695f-7b50-45b8-a4c4-4d384a7901c9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_76c8695f-7b50-45b8-a4c4-4d384a7901c9" xlink:to="loc_us-gaap_ClassOfStockDomain_76c8695f-7b50-45b8-a4c4-4d384a7901c9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_3c343afe-b91e-4047-bf89-5b8db3a02782" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_76c8695f-7b50-45b8-a4c4-4d384a7901c9" xlink:to="loc_us-gaap_ClassOfStockDomain_3c343afe-b91e-4047-bf89-5b8db3a02782" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesAPreferredStockMember_a6bd3763-3d8c-48fc-93b8-f344a7685091" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SeriesAPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3c343afe-b91e-4047-bf89-5b8db3a02782" xlink:to="loc_us-gaap_SeriesAPreferredStockMember_a6bd3763-3d8c-48fc-93b8-f344a7685091" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_SeriesajuniorparticipatingpreferredstockMember_5d49e6d1-5d25-4dea-984d-7b5a808648d5" xlink:href="cme-20231231.xsd#cme_SeriesajuniorparticipatingpreferredstockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3c343afe-b91e-4047-bf89-5b8db3a02782" xlink:to="loc_cme_SeriesajuniorparticipatingpreferredstockMember_5d49e6d1-5d25-4dea-984d-7b5a808648d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_5b9c592e-305d-459c-be07-20548cf7c5f0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3c343afe-b91e-4047-bf89-5b8db3a02782" xlink:to="loc_us-gaap_CommonClassAMember_5b9c592e-305d-459c-be07-20548cf7c5f0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_32a96466-fecc-4de5-a869-48aabe1a41b4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_3c343afe-b91e-4047-bf89-5b8db3a02782" xlink:to="loc_us-gaap_CommonClassBMember_32a96466-fecc-4de5-a869-48aabe1a41b4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_5c128aa4-7a9e-4747-b579-16a76701be37" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedBalanceSheetStatementsCaptionsLineItems_372982c5-de9a-4946-9d1c-7645c3b7ecf7" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_5c128aa4-7a9e-4747-b579-16a76701be37" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_bce27409-4234-49e4-b5fc-d08e451f4d5b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedBalanceSheetStatementsCaptionsLineItems_372982c5-de9a-4946-9d1c-7645c3b7ecf7" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_bce27409-4234-49e4-b5fc-d08e451f4d5b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsNoncurrent_2e48b77f-b4b8-4458-a09b-4901934f8365" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedCashAndCashEquivalentsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedBalanceSheetStatementsCaptionsLineItems_372982c5-de9a-4946-9d1c-7645c3b7ecf7" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsNoncurrent_2e48b77f-b4b8-4458-a09b-4901934f8365" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_32b39454-b01c-41f0-8880-4ab46687ca70" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedBalanceSheetStatementsCaptionsLineItems_372982c5-de9a-4946-9d1c-7645c3b7ecf7" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_32b39454-b01c-41f0-8880-4ab46687ca70" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_8a32bc24-b526-4148-a5b7-708a986e8c80" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedBalanceSheetStatementsCaptionsLineItems_372982c5-de9a-4946-9d1c-7645c3b7ecf7" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_8a32bc24-b526-4148-a5b7-708a986e8c80" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesIssued_150dbba0-a323-4f82-ac13-c9112ac28330" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedBalanceSheetStatementsCaptionsLineItems_372982c5-de9a-4946-9d1c-7645c3b7ecf7" xlink:to="loc_us-gaap_PreferredStockSharesIssued_150dbba0-a323-4f82-ac13-c9112ac28330" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_fc5830f4-f99d-472c-b49f-e05f5497fcf0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedBalanceSheetStatementsCaptionsLineItems_372982c5-de9a-4946-9d1c-7645c3b7ecf7" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_fc5830f4-f99d-472c-b49f-e05f5497fcf0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_a2149e20-b833-4250-8b41-90a716fbe4c9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedBalanceSheetStatementsCaptionsLineItems_372982c5-de9a-4946-9d1c-7645c3b7ecf7" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_a2149e20-b833-4250-8b41-90a716fbe4c9" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_3fe40ea5-3787-4703-b11f-3939e2e6a07f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedBalanceSheetStatementsCaptionsLineItems_372982c5-de9a-4946-9d1c-7645c3b7ecf7" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_3fe40ea5-3787-4703-b11f-3939e2e6a07f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_576106c0-e8a3-4a36-befc-55e18f3fe762" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedBalanceSheetStatementsCaptionsLineItems_372982c5-de9a-4946-9d1c-7645c3b7ecf7" xlink:to="loc_us-gaap_CommonStockSharesIssued_576106c0-e8a3-4a36-befc-55e18f3fe762" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_6e5f98ae-d4fb-48ed-88ae-a4b5507e5f9d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedBalanceSheetStatementsCaptionsLineItems_372982c5-de9a-4946-9d1c-7645c3b7ecf7" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_6e5f98ae-d4fb-48ed-88ae-a4b5507e5f9d" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/IntangibleAssetsandGoodwillTables" xlink:type="simple" xlink:href="cme-20231231.xsd#IntangibleAssetsandGoodwillTables"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/IntangibleAssetsandGoodwillTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_1d75b3e0-1543-4ad1-88da-ab7a2f9d5d96" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_4d01142d-df05-401e-acd0-fdeb1dafe431" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_1d75b3e0-1543-4ad1-88da-ab7a2f9d5d96" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_4d01142d-df05-401e-acd0-fdeb1dafe431" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_e54990a7-4a6c-4882-9f86-907bf9abfe51" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_4d01142d-df05-401e-acd0-fdeb1dafe431" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_e54990a7-4a6c-4882-9f86-907bf9abfe51" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_e54990a7-4a6c-4882-9f86-907bf9abfe51_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_e54990a7-4a6c-4882-9f86-907bf9abfe51" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_e54990a7-4a6c-4882-9f86-907bf9abfe51_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a80ecc63-82d7-406a-b3ca-dced8db623d6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_e54990a7-4a6c-4882-9f86-907bf9abfe51" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a80ecc63-82d7-406a-b3ca-dced8db623d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_fff93404-1122-4735-ab27-aa604ab4c091" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_4d01142d-df05-401e-acd0-fdeb1dafe431" xlink:to="loc_srt_ConsolidationItemsAxis_fff93404-1122-4735-ab27-aa604ab4c091" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_fff93404-1122-4735-ab27-aa604ab4c091_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_fff93404-1122-4735-ab27-aa604ab4c091" xlink:to="loc_srt_ConsolidationItemsDomain_fff93404-1122-4735-ab27-aa604ab4c091_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_4b8d0101-b3f6-4e19-a54b-0c07f2a076b5" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_fff93404-1122-4735-ab27-aa604ab4c091" xlink:to="loc_srt_ConsolidationItemsDomain_4b8d0101-b3f6-4e19-a54b-0c07f2a076b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_704b9947-68ec-4629-a10f-372746321fba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_4d01142d-df05-401e-acd0-fdeb1dafe431" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_704b9947-68ec-4629-a10f-372746321fba" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_704b9947-68ec-4629-a10f-372746321fba_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_704b9947-68ec-4629-a10f-372746321fba" xlink:to="loc_us-gaap_SegmentDomain_704b9947-68ec-4629-a10f-372746321fba_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_95888aee-de28-4ce3-a65b-aa44d5b1dade" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_704b9947-68ec-4629-a10f-372746321fba" xlink:to="loc_us-gaap_SegmentDomain_95888aee-de28-4ce3-a65b-aa44d5b1dade" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_7b4c490c-a372-4da3-9ac0-30bc4671ce28" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_4d01142d-df05-401e-acd0-fdeb1dafe431" xlink:to="loc_srt_RangeAxis_7b4c490c-a372-4da3-9ac0-30bc4671ce28" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_7b4c490c-a372-4da3-9ac0-30bc4671ce28_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_7b4c490c-a372-4da3-9ac0-30bc4671ce28" xlink:to="loc_srt_RangeMember_7b4c490c-a372-4da3-9ac0-30bc4671ce28_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_d5e53da1-7082-4aa5-bd7a-a405b045ee0a" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_7b4c490c-a372-4da3-9ac0-30bc4671ce28" xlink:to="loc_srt_RangeMember_d5e53da1-7082-4aa5-bd7a-a405b045ee0a" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/IntangibleAssetsandGoodwillGoodwillTables" xlink:type="simple" xlink:href="cme-20231231.xsd#IntangibleAssetsandGoodwillGoodwillTables"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/IntangibleAssetsandGoodwillGoodwillTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_adf5d060-5b01-40f5-96cb-50c79ae612f4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_327b7c84-7a94-4d0d-b06a-d33d971e3246" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_adf5d060-5b01-40f5-96cb-50c79ae612f4" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_327b7c84-7a94-4d0d-b06a-d33d971e3246" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_d4250505-2674-4db7-a216-d5f8925ed7d8" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_327b7c84-7a94-4d0d-b06a-d33d971e3246" xlink:to="loc_srt_ConsolidationItemsAxis_d4250505-2674-4db7-a216-d5f8925ed7d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_d4250505-2674-4db7-a216-d5f8925ed7d8_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_d4250505-2674-4db7-a216-d5f8925ed7d8" xlink:to="loc_srt_ConsolidationItemsDomain_d4250505-2674-4db7-a216-d5f8925ed7d8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_f28fe2cc-d5d6-4483-96d6-3b9d16a545b6" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_d4250505-2674-4db7-a216-d5f8925ed7d8" xlink:to="loc_srt_ConsolidationItemsDomain_f28fe2cc-d5d6-4483-96d6-3b9d16a545b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_278071dc-59eb-4f0d-b101-345c6e8524aa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_327b7c84-7a94-4d0d-b06a-d33d971e3246" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_278071dc-59eb-4f0d-b101-345c6e8524aa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_278071dc-59eb-4f0d-b101-345c6e8524aa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_278071dc-59eb-4f0d-b101-345c6e8524aa" xlink:to="loc_us-gaap_SegmentDomain_278071dc-59eb-4f0d-b101-345c6e8524aa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_a4d691bf-c723-4f5d-a614-890f8e85e56f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_278071dc-59eb-4f0d-b101-345c6e8524aa" xlink:to="loc_us-gaap_SegmentDomain_a4d691bf-c723-4f5d-a614-890f8e85e56f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_45a05212-4326-41cd-8091-afc07cf0f6fd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_327b7c84-7a94-4d0d-b06a-d33d971e3246" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_45a05212-4326-41cd-8091-afc07cf0f6fd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_45a05212-4326-41cd-8091-afc07cf0f6fd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_45a05212-4326-41cd-8091-afc07cf0f6fd" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_45a05212-4326-41cd-8091-afc07cf0f6fd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_beeb6d90-2f24-4302-b7bc-fd0e7d583b9c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_45a05212-4326-41cd-8091-afc07cf0f6fd" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_beeb6d90-2f24-4302-b7bc-fd0e7d583b9c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_97d149f8-19f4-44f3-99f3-a60261adf46c" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_327b7c84-7a94-4d0d-b06a-d33d971e3246" xlink:to="loc_srt_RangeAxis_97d149f8-19f4-44f3-99f3-a60261adf46c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_97d149f8-19f4-44f3-99f3-a60261adf46c_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_97d149f8-19f4-44f3-99f3-a60261adf46c" xlink:to="loc_srt_RangeMember_97d149f8-19f4-44f3-99f3-a60261adf46c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2afe3016-a369-4aac-ac99-7453f83cc6af" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_97d149f8-19f4-44f3-99f3-a60261adf46c" xlink:to="loc_srt_RangeMember_2afe3016-a369-4aac-ac99-7453f83cc6af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitAxis_4701a36f-7a9c-4be3-b52a-023e3ba2c085" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReportingUnitAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_327b7c84-7a94-4d0d-b06a-d33d971e3246" xlink:to="loc_us-gaap_ReportingUnitAxis_4701a36f-7a9c-4be3-b52a-023e3ba2c085" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitDomain_4701a36f-7a9c-4be3-b52a-023e3ba2c085_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReportingUnitDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReportingUnitAxis_4701a36f-7a9c-4be3-b52a-023e3ba2c085" xlink:to="loc_us-gaap_ReportingUnitDomain_4701a36f-7a9c-4be3-b52a-023e3ba2c085_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitDomain_3eca5a83-899b-4cf1-b391-417ac463e02d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReportingUnitDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReportingUnitAxis_4701a36f-7a9c-4be3-b52a-023e3ba2c085" xlink:to="loc_us-gaap_ReportingUnitDomain_3eca5a83-899b-4cf1-b391-417ac463e02d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillDisclosureTextBlock_bef54e0c-e44b-45c3-ad89-1e081cee0f66" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillDisclosureTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_adf5d060-5b01-40f5-96cb-50c79ae612f4" xlink:to="loc_us-gaap_GoodwillDisclosureTextBlock_bef54e0c-e44b-45c3-ad89-1e081cee0f66" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/DebtTables" xlink:type="simple" xlink:href="cme-20231231.xsd#DebtTables"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/DebtTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtLineItems_5ab12d9b-5f1b-48d8-bf44-e00123412cb5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermDebtLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShortTermDebtTable_cdeeb18e-c897-4d80-8e71-5174f57a8fa1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShortTermDebtTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortTermDebtLineItems_5ab12d9b-5f1b-48d8-bf44-e00123412cb5" xlink:to="loc_us-gaap_ScheduleOfShortTermDebtTable_cdeeb18e-c897-4d80-8e71-5174f57a8fa1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_35b65960-1302-4d62-bf04-5b4e8bf2d2d3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_cdeeb18e-c897-4d80-8e71-5174f57a8fa1" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_35b65960-1302-4d62-bf04-5b4e8bf2d2d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_35b65960-1302-4d62-bf04-5b4e8bf2d2d3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_35b65960-1302-4d62-bf04-5b4e8bf2d2d3" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_35b65960-1302-4d62-bf04-5b4e8bf2d2d3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_227a51f7-40c4-42e9-aedd-06f4ed0bf474" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_35b65960-1302-4d62-bf04-5b4e8bf2d2d3" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_227a51f7-40c4-42e9-aedd-06f4ed0bf474" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_691aa767-8aa4-4ad5-81ca-4a6e3c4473b9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_cdeeb18e-c897-4d80-8e71-5174f57a8fa1" xlink:to="loc_us-gaap_DebtInstrumentAxis_691aa767-8aa4-4ad5-81ca-4a6e3c4473b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_691aa767-8aa4-4ad5-81ca-4a6e3c4473b9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_691aa767-8aa4-4ad5-81ca-4a6e3c4473b9" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_691aa767-8aa4-4ad5-81ca-4a6e3c4473b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_f9a4a4a0-c96e-4487-bffa-6cfc98cc5bbc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_691aa767-8aa4-4ad5-81ca-4a6e3c4473b9" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_f9a4a4a0-c96e-4487-bffa-6cfc98cc5bbc" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/CommitmentsTables" xlink:type="simple" xlink:href="cme-20231231.xsd#CommitmentsTables"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/CommitmentsTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_b36de139-d1f6-4507-9641-5654a741318d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_925a9b0a-4d11-40f3-9c49-56b2410d08a1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_b36de139-d1f6-4507-9641-5654a741318d" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_925a9b0a-4d11-40f3-9c49-56b2410d08a1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis_6fb46fa2-d3d9-45d8-b09b-6ec857c81116" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_925a9b0a-4d11-40f3-9c49-56b2410d08a1" xlink:to="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis_6fb46fa2-d3d9-45d8-b09b-6ec857c81116" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain_6fb46fa2-d3d9-45d8-b09b-6ec857c81116_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis_6fb46fa2-d3d9-45d8-b09b-6ec857c81116" xlink:to="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain_6fb46fa2-d3d9-45d8-b09b-6ec857c81116_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain_3fa3994d-b130-4838-adf1-84fbc20f256e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis_6fb46fa2-d3d9-45d8-b09b-6ec857c81116" xlink:to="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain_3fa3994d-b130-4838-adf1-84fbc20f256e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertySubjectToOperatingLeaseMember_82e88e03-b78e-46e0-a5e4-7caadcb5621e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertySubjectToOperatingLeaseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain_3fa3994d-b130-4838-adf1-84fbc20f256e" xlink:to="loc_us-gaap_PropertySubjectToOperatingLeaseMember_82e88e03-b78e-46e0-a5e4-7caadcb5621e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_PropertySubjecttoFinanceLeaseMember_81cbb5f8-ad3f-424d-9bfc-71dd2cce4e7a" xlink:href="cme-20231231.xsd#cme_PropertySubjecttoFinanceLeaseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain_3fa3994d-b130-4838-adf1-84fbc20f256e" xlink:to="loc_cme_PropertySubjecttoFinanceLeaseMember_81cbb5f8-ad3f-424d-9bfc-71dd2cce4e7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCashFlowSupplementalDisclosuresTableTextBlock_d7beccaf-4e7d-4951-903f-6542ad78179a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfCashFlowSupplementalDisclosuresTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_b36de139-d1f6-4507-9641-5654a741318d" xlink:to="loc_us-gaap_ScheduleOfCashFlowSupplementalDisclosuresTableTextBlock_d7beccaf-4e7d-4951-903f-6542ad78179a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock_35ab1f5c-d57f-429f-999a-abff0d85d35a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_b36de139-d1f6-4507-9641-5654a741318d" xlink:to="loc_us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock_35ab1f5c-d57f-429f-999a-abff0d85d35a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCostTableTextBlock_09d170f0-75c4-4a4c-8435-ea87577a17e5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LeaseCostTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_b36de139-d1f6-4507-9641-5654a741318d" xlink:to="loc_us-gaap_LeaseCostTableTextBlock_09d170f0-75c4-4a4c-8435-ea87577a17e5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_68bfc272-3ab3-4f4b-84a2-25e491189d1b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_b36de139-d1f6-4507-9641-5654a741318d" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_68bfc272-3ab3-4f4b-84a2-25e491189d1b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock_5e9af43f-d85e-4765-8346-053dd455ccbc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_b36de139-d1f6-4507-9641-5654a741318d" xlink:to="loc_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock_5e9af43f-d85e-4765-8346-053dd455ccbc" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/SummaryofSignificantAccountingPoliciesNarrativeDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#SummaryofSignificantAccountingPoliciesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/SummaryofSignificantAccountingPoliciesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_fdac3e62-5003-431d-9a31-c5571c000514" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_0e47061e-2700-4e1f-b7f5-28f4ab2ad9f3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_fdac3e62-5003-431d-9a31-c5571c000514" xlink:to="loc_us-gaap_StatementTable_0e47061e-2700-4e1f-b7f5-28f4ab2ad9f3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_2fdc2b23-767c-4d0f-a804-404f1d8302e9" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0e47061e-2700-4e1f-b7f5-28f4ab2ad9f3" xlink:to="loc_srt_RangeAxis_2fdc2b23-767c-4d0f-a804-404f1d8302e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2fdc2b23-767c-4d0f-a804-404f1d8302e9_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_2fdc2b23-767c-4d0f-a804-404f1d8302e9" xlink:to="loc_srt_RangeMember_2fdc2b23-767c-4d0f-a804-404f1d8302e9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_9ad3c9d1-c1c5-423a-89a9-0b5e68f6a81a" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_2fdc2b23-767c-4d0f-a804-404f1d8302e9" xlink:to="loc_srt_RangeMember_9ad3c9d1-c1c5-423a-89a9-0b5e68f6a81a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_a977b4d0-bc8f-45bf-ab15-51e5aa15a317" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9ad3c9d1-c1c5-423a-89a9-0b5e68f6a81a" xlink:to="loc_srt_MinimumMember_a977b4d0-bc8f-45bf-ab15-51e5aa15a317" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_a5b86f6a-7d3c-4a3d-a134-4f05c9293528" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9ad3c9d1-c1c5-423a-89a9-0b5e68f6a81a" xlink:to="loc_srt_MaximumMember_a5b86f6a-7d3c-4a3d-a134-4f05c9293528" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_6db690cf-0d58-4d4b-b4f9-31a1c6ccda03" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0e47061e-2700-4e1f-b7f5-28f4ab2ad9f3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_6db690cf-0d58-4d4b-b4f9-31a1c6ccda03" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6db690cf-0d58-4d4b-b4f9-31a1c6ccda03_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_6db690cf-0d58-4d4b-b4f9-31a1c6ccda03" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6db690cf-0d58-4d4b-b4f9-31a1c6ccda03_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_76e90799-d097-423d-86e3-5c32e6a8c5d9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_6db690cf-0d58-4d4b-b4f9-31a1c6ccda03" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_76e90799-d097-423d-86e3-5c32e6a8c5d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_cb80910a-7555-4a85-8289-7ae8826b0024" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SoftwareAndSoftwareDevelopmentCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_76e90799-d097-423d-86e3-5c32e6a8c5d9" xlink:to="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_cb80910a-7555-4a85-8289-7ae8826b0024" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_9dc77523-e9ca-4b8e-876d-4f8e056cb42f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0e47061e-2700-4e1f-b7f5-28f4ab2ad9f3" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_9dc77523-e9ca-4b8e-876d-4f8e056cb42f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_9dc77523-e9ca-4b8e-876d-4f8e056cb42f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_9dc77523-e9ca-4b8e-876d-4f8e056cb42f" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_9dc77523-e9ca-4b8e-876d-4f8e056cb42f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_3021fa4f-415f-4a21-8900-217848cbf345" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_9dc77523-e9ca-4b8e-876d-4f8e056cb42f" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_3021fa4f-415f-4a21-8900-217848cbf345" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClearingandtransactionfeesMember_8f06721f-3246-442f-911d-21ebada4fd90" xlink:href="cme-20231231.xsd#cme_ClearingandtransactionfeesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_3021fa4f-415f-4a21-8900-217848cbf345" xlink:to="loc_cme_ClearingandtransactionfeesMember_8f06721f-3246-442f-911d-21ebada4fd90" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_SalesRevenueMarketDataAndInformationServicesMember_4b007695-a529-4c29-96cc-681019ebc7fe" xlink:href="cme-20231231.xsd#cme_SalesRevenueMarketDataAndInformationServicesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_3021fa4f-415f-4a21-8900-217848cbf345" xlink:to="loc_cme_SalesRevenueMarketDataAndInformationServicesMember_4b007695-a529-4c29-96cc-681019ebc7fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_07066fa0-0d7f-4285-9900-e4dd8cea7ddb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0e47061e-2700-4e1f-b7f5-28f4ab2ad9f3" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_07066fa0-0d7f-4285-9900-e4dd8cea7ddb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_07066fa0-0d7f-4285-9900-e4dd8cea7ddb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_07066fa0-0d7f-4285-9900-e4dd8cea7ddb" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_07066fa0-0d7f-4285-9900-e4dd8cea7ddb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_512c2cf9-3d11-40d0-aa41-c8b5f661777e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_07066fa0-0d7f-4285-9900-e4dd8cea7ddb" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_512c2cf9-3d11-40d0-aa41-c8b5f661777e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClearingandtransactionfeesMember_d85eefe1-7e28-4b3a-937c-ab42c7308a99" xlink:href="cme-20231231.xsd#cme_ClearingandtransactionfeesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_512c2cf9-3d11-40d0-aa41-c8b5f661777e" xlink:to="loc_cme_ClearingandtransactionfeesMember_d85eefe1-7e28-4b3a-937c-ab42c7308a99" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_SalesRevenueMarketDataAndInformationServicesMember_8a850394-1dcc-45d1-8f37-00d4f038f4e8" xlink:href="cme-20231231.xsd#cme_SalesRevenueMarketDataAndInformationServicesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_512c2cf9-3d11-40d0-aa41-c8b5f661777e" xlink:to="loc_cme_SalesRevenueMarketDataAndInformationServicesMember_8a850394-1dcc-45d1-8f37-00d4f038f4e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ConcentrationRiskThresholdPercentageAxis_5f1f9c4c-8d41-40c8-9ba0-36ae2a79563f" xlink:href="cme-20231231.xsd#cme_ConcentrationRiskThresholdPercentageAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0e47061e-2700-4e1f-b7f5-28f4ab2ad9f3" xlink:to="loc_cme_ConcentrationRiskThresholdPercentageAxis_5f1f9c4c-8d41-40c8-9ba0-36ae2a79563f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ConcentrationRiskThresholdPercentageDomain_5f1f9c4c-8d41-40c8-9ba0-36ae2a79563f_default" xlink:href="cme-20231231.xsd#cme_ConcentrationRiskThresholdPercentageDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_cme_ConcentrationRiskThresholdPercentageAxis_5f1f9c4c-8d41-40c8-9ba0-36ae2a79563f" xlink:to="loc_cme_ConcentrationRiskThresholdPercentageDomain_5f1f9c4c-8d41-40c8-9ba0-36ae2a79563f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ConcentrationRiskThresholdPercentageDomain_33ca5e96-35b5-4ba2-a92a-57911b1f214e" xlink:href="cme-20231231.xsd#cme_ConcentrationRiskThresholdPercentageDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_cme_ConcentrationRiskThresholdPercentageAxis_5f1f9c4c-8d41-40c8-9ba0-36ae2a79563f" xlink:to="loc_cme_ConcentrationRiskThresholdPercentageDomain_33ca5e96-35b5-4ba2-a92a-57911b1f214e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_SalesRevenueMarketDataAndInformationServicesMember_bb6cd097-5025-466d-b662-8f1cb32d7e68" xlink:href="cme-20231231.xsd#cme_SalesRevenueMarketDataAndInformationServicesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cme_ConcentrationRiskThresholdPercentageDomain_33ca5e96-35b5-4ba2-a92a-57911b1f214e" xlink:to="loc_cme_SalesRevenueMarketDataAndInformationServicesMember_bb6cd097-5025-466d-b662-8f1cb32d7e68" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClearingandtransactionfeesMember_823296b0-3599-4353-8146-f031483a41f8" xlink:href="cme-20231231.xsd#cme_ClearingandtransactionfeesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cme_ConcentrationRiskThresholdPercentageDomain_33ca5e96-35b5-4ba2-a92a-57911b1f214e" xlink:to="loc_cme_ClearingandtransactionfeesMember_823296b0-3599-4353-8146-f031483a41f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_12e49f4c-e0be-4fea-a97c-c389decfe254" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_fdac3e62-5003-431d-9a31-c5571c000514" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_12e49f4c-e0be-4fea-a97c-c389decfe254" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_b767ec2e-fee9-4009-bbb6-06ef2aa2bd29" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_fdac3e62-5003-431d-9a31-c5571c000514" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_b767ec2e-fee9-4009-bbb6-06ef2aa2bd29" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/RevenueRecognitionDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#RevenueRecognitionDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/RevenueRecognitionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_ef263f82-24bb-4554-8fcd-a59ac65a338c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_54f5883d-da29-4f72-8d6c-2c8dc5249a6f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_ef263f82-24bb-4554-8fcd-a59ac65a338c" xlink:to="loc_us-gaap_StatementTable_54f5883d-da29-4f72-8d6c-2c8dc5249a6f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_19e8f45c-5331-4aac-b16e-2332829f1160" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TimingOfTransferOfGoodOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_54f5883d-da29-4f72-8d6c-2c8dc5249a6f" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_19e8f45c-5331-4aac-b16e-2332829f1160" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_19e8f45c-5331-4aac-b16e-2332829f1160_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_19e8f45c-5331-4aac-b16e-2332829f1160" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_19e8f45c-5331-4aac-b16e-2332829f1160_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_1400538e-af8c-49ff-8eb3-32fdf095d26e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_19e8f45c-5331-4aac-b16e-2332829f1160" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_1400538e-af8c-49ff-8eb3-32fdf095d26e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredAtPointInTimeMember_ea0117af-62c6-437a-96ef-93d978a7b7f4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransferredAtPointInTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_1400538e-af8c-49ff-8eb3-32fdf095d26e" xlink:to="loc_us-gaap_TransferredAtPointInTimeMember_ea0117af-62c6-437a-96ef-93d978a7b7f4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredOverTimeMember_b1671800-5a9b-4399-90f2-3ff9355615ea" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransferredOverTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_1400538e-af8c-49ff-8eb3-32fdf095d26e" xlink:to="loc_us-gaap_TransferredOverTimeMember_b1671800-5a9b-4399-90f2-3ff9355615ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_OnetimechargesandmiscellaneousrevenuesMember_7ed1016d-71ff-49b8-9928-ac4b93cf0b0d" xlink:href="cme-20231231.xsd#cme_OnetimechargesandmiscellaneousrevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_1400538e-af8c-49ff-8eb3-32fdf095d26e" xlink:to="loc_cme_OnetimechargesandmiscellaneousrevenuesMember_7ed1016d-71ff-49b8-9928-ac4b93cf0b0d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_77e924d0-8af9-4a82-85b3-8dbe74b606b2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_54f5883d-da29-4f72-8d6c-2c8dc5249a6f" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_77e924d0-8af9-4a82-85b3-8dbe74b606b2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_77e924d0-8af9-4a82-85b3-8dbe74b606b2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_77e924d0-8af9-4a82-85b3-8dbe74b606b2" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_77e924d0-8af9-4a82-85b3-8dbe74b606b2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_5591ff35-5212-4829-bbef-4acfb60f4877" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_77e924d0-8af9-4a82-85b3-8dbe74b606b2" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_5591ff35-5212-4829-bbef-4acfb60f4877" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_InterestRateMember_04fefb77-02e8-47e9-8956-e8e325bb6650" xlink:href="cme-20231231.xsd#cme_InterestRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5591ff35-5212-4829-bbef-4acfb60f4877" xlink:to="loc_cme_InterestRateMember_04fefb77-02e8-47e9-8956-e8e325bb6650" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_EquitiesMember_155ca2b1-0290-4168-b424-212e94bc39c6" xlink:href="cme-20231231.xsd#cme_EquitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5591ff35-5212-4829-bbef-4acfb60f4877" xlink:to="loc_cme_EquitiesMember_155ca2b1-0290-4168-b424-212e94bc39c6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeMember_26c7ce5f-5b28-4f49-9b5a-2f22e4e5db91" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ForeignExchangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5591ff35-5212-4829-bbef-4acfb60f4877" xlink:to="loc_us-gaap_ForeignExchangeMember_26c7ce5f-5b28-4f49-9b5a-2f22e4e5db91" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_AgriculturalcommodityMember_759a4855-f197-4312-a3bb-4e1ddbea0255" xlink:href="cme-20231231.xsd#cme_AgriculturalcommodityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5591ff35-5212-4829-bbef-4acfb60f4877" xlink:to="loc_cme_AgriculturalcommodityMember_759a4855-f197-4312-a3bb-4e1ddbea0255" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_EnergyMember_156e02bd-fcd9-45d9-b4ba-8dcf5e2beaad" xlink:href="cme-20231231.xsd#cme_EnergyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5591ff35-5212-4829-bbef-4acfb60f4877" xlink:to="loc_cme_EnergyMember_156e02bd-fcd9-45d9-b4ba-8dcf5e2beaad" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_MetalMember_4b29db71-226e-4217-8229-62e33cca7947" xlink:href="cme-20231231.xsd#cme_MetalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5591ff35-5212-4829-bbef-4acfb60f4877" xlink:to="loc_cme_MetalMember_4b29db71-226e-4217-8229-62e33cca7947" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OverTheCounterMember_e656d805-ece3-400a-9423-38ed82e2dc9a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OverTheCounterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5591ff35-5212-4829-bbef-4acfb60f4877" xlink:to="loc_us-gaap_OverTheCounterMember_e656d805-ece3-400a-9423-38ed82e2dc9a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_BrokerTecFixedIncomeMember_9ff4c8da-194d-4072-aef2-0fa7a9df285c" xlink:href="cme-20231231.xsd#cme_BrokerTecFixedIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5591ff35-5212-4829-bbef-4acfb60f4877" xlink:to="loc_cme_BrokerTecFixedIncomeMember_9ff4c8da-194d-4072-aef2-0fa7a9df285c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_EBSForeignExchangeMember_203a456c-d157-4359-9fd5-282aa8fbab91" xlink:href="cme-20231231.xsd#cme_EBSForeignExchangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5591ff35-5212-4829-bbef-4acfb60f4877" xlink:to="loc_cme_EBSForeignExchangeMember_203a456c-d157-4359-9fd5-282aa8fbab91" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_OptimizationMember_deb0c6ac-b915-4eb5-aae3-9964243e19b3" xlink:href="cme-20231231.xsd#cme_OptimizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5591ff35-5212-4829-bbef-4acfb60f4877" xlink:to="loc_cme_OptimizationMember_deb0c6ac-b915-4eb5-aae3-9964243e19b3" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_c0013676-7b24-4e2a-a6a3-94b1731db209" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_54f5883d-da29-4f72-8d6c-2c8dc5249a6f" xlink:to="loc_srt_ProductOrServiceAxis_c0013676-7b24-4e2a-a6a3-94b1731db209" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_c0013676-7b24-4e2a-a6a3-94b1731db209_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_c0013676-7b24-4e2a-a6a3-94b1731db209" xlink:to="loc_srt_ProductsAndServicesDomain_c0013676-7b24-4e2a-a6a3-94b1731db209_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_e7048c2c-f75d-471b-8797-d102b8963ce7" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_c0013676-7b24-4e2a-a6a3-94b1731db209" xlink:to="loc_srt_ProductsAndServicesDomain_e7048c2c-f75d-471b-8797-d102b8963ce7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClearingandtransactionfeesMember_f85421cc-73f2-411a-8115-e0d10e8d8529" xlink:href="cme-20231231.xsd#cme_ClearingandtransactionfeesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_e7048c2c-f75d-471b-8797-d102b8963ce7" xlink:to="loc_cme_ClearingandtransactionfeesMember_f85421cc-73f2-411a-8115-e0d10e8d8529" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_MarketDataMember_c8fb270f-bc92-4eb2-bb5f-d0dbc9379251" xlink:href="cme-20231231.xsd#cme_MarketDataMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_e7048c2c-f75d-471b-8797-d102b8963ce7" xlink:to="loc_cme_MarketDataMember_c8fb270f-bc92-4eb2-bb5f-d0dbc9379251" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_OtherRevenueMember_0b62a92d-9459-4f6c-9ba1-9bf4f7a45f4c" xlink:href="cme-20231231.xsd#cme_OtherRevenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_e7048c2c-f75d-471b-8797-d102b8963ce7" xlink:to="loc_cme_OtherRevenueMember_0b62a92d-9459-4f6c-9ba1-9bf4f7a45f4c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_fc10523f-ff8a-453e-bcbd-9c9d1e2dafa0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ef263f82-24bb-4554-8fcd-a59ac65a338c" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_fc10523f-ff8a-453e-bcbd-9c9d1e2dafa0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_de37de33-d185-446e-9296-528bee8d8e2b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ef263f82-24bb-4554-8fcd-a59ac65a338c" xlink:to="loc_us-gaap_Revenues_de37de33-d185-446e-9296-528bee8d8e2b" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/PerformanceBondsandGuarantyFundContributionsNarrativeDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#PerformanceBondsandGuarantyFundContributionsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/PerformanceBondsandGuarantyFundContributionsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_ac44f9a6-9867-448f-a64f-adc42f14e450" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_0b066865-9cad-4eda-a815-3584233e7e84" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_ac44f9a6-9867-448f-a64f-adc42f14e450" xlink:to="loc_us-gaap_StatementTable_0b066865-9cad-4eda-a815-3584233e7e84" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsByNatureAxis_0340acb0-0d05-4f04-89ca-ed3ea7d643ce" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GuaranteeObligationsByNatureAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0b066865-9cad-4eda-a815-3584233e7e84" xlink:to="loc_us-gaap_GuaranteeObligationsByNatureAxis_0340acb0-0d05-4f04-89ca-ed3ea7d643ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_0340acb0-0d05-4f04-89ca-ed3ea7d643ce_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_0340acb0-0d05-4f04-89ca-ed3ea7d643ce" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_0340acb0-0d05-4f04-89ca-ed3ea7d643ce_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_8fd2c657-2f4c-4a60-b816-3e5e765beaad" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_0340acb0-0d05-4f04-89ca-ed3ea7d643ce" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_8fd2c657-2f4c-4a60-b816-3e5e765beaad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_FederalReserveReinvestmentMember_4ef42331-4673-4578-89e0-1d03903bf2c2" xlink:href="cme-20231231.xsd#cme_FederalReserveReinvestmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_8fd2c657-2f4c-4a60-b816-3e5e765beaad" xlink:to="loc_cme_FederalReserveReinvestmentMember_4ef42331-4673-4578-89e0-1d03903bf2c2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_GuarantyFundAxis_9c306091-9837-419e-bf5a-63a5c92a0364" xlink:href="cme-20231231.xsd#cme_GuarantyFundAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0b066865-9cad-4eda-a815-3584233e7e84" xlink:to="loc_cme_GuarantyFundAxis_9c306091-9837-419e-bf5a-63a5c92a0364" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_GuarantyFundDomain_9c306091-9837-419e-bf5a-63a5c92a0364_default" xlink:href="cme-20231231.xsd#cme_GuarantyFundDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_cme_GuarantyFundAxis_9c306091-9837-419e-bf5a-63a5c92a0364" xlink:to="loc_cme_GuarantyFundDomain_9c306091-9837-419e-bf5a-63a5c92a0364_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_GuarantyFundDomain_841d8b83-0a73-43ee-b5a4-f210ace591a9" xlink:href="cme-20231231.xsd#cme_GuarantyFundDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_cme_GuarantyFundAxis_9c306091-9837-419e-bf5a-63a5c92a0364" xlink:to="loc_cme_GuarantyFundDomain_841d8b83-0a73-43ee-b5a4-f210ace591a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_CmeBaseGuarantyFundMember_e5fa3127-6992-4ed6-a912-a7b2aa6d0e5d" xlink:href="cme-20231231.xsd#cme_CmeBaseGuarantyFundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cme_GuarantyFundDomain_841d8b83-0a73-43ee-b5a4-f210ace591a9" xlink:to="loc_cme_CmeBaseGuarantyFundMember_e5fa3127-6992-4ed6-a912-a7b2aa6d0e5d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_CmeIrsGuarantyFundMemberMember_fc81d4af-fd8a-4f16-ae5d-8b0f18c7255a" xlink:href="cme-20231231.xsd#cme_CmeIrsGuarantyFundMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cme_GuarantyFundDomain_841d8b83-0a73-43ee-b5a4-f210ace591a9" xlink:to="loc_cme_CmeIrsGuarantyFundMemberMember_fc81d4af-fd8a-4f16-ae5d-8b0f18c7255a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityAxis_4391ad4d-e069-4163-852b-92eb08a5f045" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0b066865-9cad-4eda-a815-3584233e7e84" xlink:to="loc_us-gaap_LineOfCreditFacilityAxis_4391ad4d-e069-4163-852b-92eb08a5f045" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_4391ad4d-e069-4163-852b-92eb08a5f045_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityLenderDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_4391ad4d-e069-4163-852b-92eb08a5f045" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_4391ad4d-e069-4163-852b-92eb08a5f045_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_bbcd4310-5ae1-4f9f-baf9-b09ba052ca40" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityLenderDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_4391ad4d-e069-4163-852b-92eb08a5f045" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_bbcd4310-5ae1-4f9f-baf9-b09ba052ca40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_LineOfCreditFacilityFullySecuredCommittedMember_bd2ba673-3cf1-4a1e-b198-8b923ec59d7d" xlink:href="cme-20231231.xsd#cme_LineOfCreditFacilityFullySecuredCommittedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_bbcd4310-5ae1-4f9f-baf9-b09ba052ca40" xlink:to="loc_cme_LineOfCreditFacilityFullySecuredCommittedMember_bd2ba673-3cf1-4a1e-b198-8b923ec59d7d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_LetterOfCreditFacilityRevolvingSeniorCreditFacilityMember_419aed7e-10fb-465b-802d-df69949ba929" xlink:href="cme-20231231.xsd#cme_LetterOfCreditFacilityRevolvingSeniorCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_bbcd4310-5ae1-4f9f-baf9-b09ba052ca40" xlink:to="loc_cme_LetterOfCreditFacilityRevolvingSeniorCreditFacilityMember_419aed7e-10fb-465b-802d-df69949ba929" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashEquivalentsAtCarryingValue_870fff9b-df8a-40bb-b4e0-892c8d9c5537" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ac44f9a6-9867-448f-a64f-adc42f14e450" xlink:to="loc_us-gaap_CashEquivalentsAtCarryingValue_870fff9b-df8a-40bb-b4e0-892c8d9c5537" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_PercentageShareOfCrossMarginingCollateral_d223c931-f3ba-44d7-a976-d6f2401e5714" xlink:href="cme-20231231.xsd#cme_PercentageShareOfCrossMarginingCollateral"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ac44f9a6-9867-448f-a64f-adc42f14e450" xlink:to="loc_cme_PercentageShareOfCrossMarginingCollateral_d223c931-f3ba-44d7-a976-d6f2401e5714" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_CorporateContribution_1f5f68ce-46a9-4a43-93c8-7bbd3c43f005" xlink:href="cme-20231231.xsd#cme_CorporateContribution"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ac44f9a6-9867-448f-a64f-adc42f14e450" xlink:to="loc_cme_CorporateContribution_1f5f68ce-46a9-4a43-93c8-7bbd3c43f005" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_GuarantyFundContributions_3f6c1905-5bbd-4ad4-bcf5-4b7012405ca0" xlink:href="cme-20231231.xsd#cme_GuarantyFundContributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ac44f9a6-9867-448f-a64f-adc42f14e450" xlink:to="loc_cme_GuarantyFundContributions_3f6c1905-5bbd-4ad4-bcf5-4b7012405ca0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_cde95cde-2d4a-4e8f-80a2-09fd5c2090eb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ac44f9a6-9867-448f-a64f-adc42f14e450" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_cde95cde-2d4a-4e8f-80a2-09fd5c2090eb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_LineOfCreditGuarantyFundCollateralAvailable_584c0aef-ac07-4b0c-a707-09a5ce7ae4e6" xlink:href="cme-20231231.xsd#cme_LineOfCreditGuarantyFundCollateralAvailable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ac44f9a6-9867-448f-a64f-adc42f14e450" xlink:to="loc_cme_LineOfCreditGuarantyFundCollateralAvailable_584c0aef-ac07-4b0c-a707-09a5ce7ae4e6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_LineOfCreditFacilityOptionToIncreaseMaximumBorrowingCapacity_04199ffc-5a9c-45bf-ae50-d7199cc83e2c" xlink:href="cme-20231231.xsd#cme_LineOfCreditFacilityOptionToIncreaseMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ac44f9a6-9867-448f-a64f-adc42f14e450" xlink:to="loc_cme_LineOfCreditFacilityOptionToIncreaseMaximumBorrowingCapacity_04199ffc-5a9c-45bf-ae50-d7199cc83e2c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_CommittedLineOfCreditNumberOfDaysFullySecured_c2cf88cf-991e-42d4-8549-fef0320d4fd7" xlink:href="cme-20231231.xsd#cme_CommittedLineOfCreditNumberOfDaysFullySecured"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ac44f9a6-9867-448f-a64f-adc42f14e450" xlink:to="loc_cme_CommittedLineOfCreditNumberOfDaysFullySecured_c2cf88cf-991e-42d4-8549-fef0320d4fd7" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_IntradaySettlementsOfCashPerformanceBonds_4170b722-9f5b-419a-a4d8-468bc21f72d1" xlink:href="cme-20231231.xsd#cme_IntradaySettlementsOfCashPerformanceBonds"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ac44f9a6-9867-448f-a64f-adc42f14e450" xlink:to="loc_cme_IntradaySettlementsOfCashPerformanceBonds_4170b722-9f5b-419a-a4d8-468bc21f72d1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_AverageDailyClearingSettlement_a5f2b8ae-5d9f-471d-a519-4fe908ec9e65" xlink:href="cme-20231231.xsd#cme_AverageDailyClearingSettlement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ac44f9a6-9867-448f-a64f-adc42f14e450" xlink:to="loc_cme_AverageDailyClearingSettlement_a5f2b8ae-5d9f-471d-a519-4fe908ec9e65" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/PerformanceBondsandGuarantyFundContributionsCashandSecuritiesHeldasPerformanceBondsandGuarantyFundContributionsatFairValueDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#PerformanceBondsandGuarantyFundContributionsCashandSecuritiesHeldasPerformanceBondsandGuarantyFundContributionsatFairValueDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/PerformanceBondsandGuarantyFundContributionsCashandSecuritiesHeldasPerformanceBondsandGuarantyFundContributionsatFairValueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_4724d043-c529-4105-9ef0-500ab2ed98ba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_ac6ad181-c8e2-4045-8385-67f246ae049f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_4724d043-c529-4105-9ef0-500ab2ed98ba" xlink:to="loc_us-gaap_StatementTable_ac6ad181-c8e2-4045-8385-67f246ae049f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_f7c029dd-9e95-4eac-9292-e603beac3227" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_ac6ad181-c8e2-4045-8385-67f246ae049f" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_f7c029dd-9e95-4eac-9292-e603beac3227" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_f7c029dd-9e95-4eac-9292-e603beac3227_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_f7c029dd-9e95-4eac-9292-e603beac3227" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_f7c029dd-9e95-4eac-9292-e603beac3227_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_bcbd32e3-f1bf-4db2-99e6-6cd9278f5688" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_f7c029dd-9e95-4eac-9292-e603beac3227" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_bcbd32e3-f1bf-4db2-99e6-6cd9278f5688" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashMember_d4ada9f7-97e8-4ea1-b588-272a7363add2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_bcbd32e3-f1bf-4db2-99e6-6cd9278f5688" xlink:to="loc_us-gaap_CashMember_d4ada9f7-97e8-4ea1-b588-272a7363add2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_SecuritiesAndIefFundsMember_cd245373-6275-496c-b710-c4c57f8ecd67" xlink:href="cme-20231231.xsd#cme_SecuritiesAndIefFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_bcbd32e3-f1bf-4db2-99e6-6cd9278f5688" xlink:to="loc_cme_SecuritiesAndIefFundsMember_cd245373-6275-496c-b710-c4c57f8ecd67" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_PerformanceBonds_86dd60a4-634d-4f8b-9ab4-a4d9a3c04470" xlink:href="cme-20231231.xsd#cme_PerformanceBonds"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4724d043-c529-4105-9ef0-500ab2ed98ba" xlink:to="loc_cme_PerformanceBonds_86dd60a4-634d-4f8b-9ab4-a4d9a3c04470" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_GuarantyFundContributions_ffbb6ac4-49f9-4cf1-bece-e9435aa95311" xlink:href="cme-20231231.xsd#cme_GuarantyFundContributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4724d043-c529-4105-9ef0-500ab2ed98ba" xlink:to="loc_cme_GuarantyFundContributions_ffbb6ac4-49f9-4cf1-bece-e9435aa95311" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_CrossMarginArrangements_a0068ca1-d5f0-41cf-bb90-a583c3e30774" xlink:href="cme-20231231.xsd#cme_CrossMarginArrangements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4724d043-c529-4105-9ef0-500ab2ed98ba" xlink:to="loc_cme_CrossMarginArrangements_a0068ca1-d5f0-41cf-bb90-a583c3e30774" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_PerformanceCollateralForDelivery_dc053df6-45f4-4d3f-8fe3-02359a5ea0c7" xlink:href="cme-20231231.xsd#cme_PerformanceCollateralForDelivery"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4724d043-c529-4105-9ef0-500ab2ed98ba" xlink:to="loc_cme_PerformanceCollateralForDelivery_dc053df6-45f4-4d3f-8fe3-02359a5ea0c7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodFaithAndMarginDepositsWithBrokerDealers_9cf803a4-d1c5-44de-a16c-9f2c44890a69" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodFaithAndMarginDepositsWithBrokerDealers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4724d043-c529-4105-9ef0-500ab2ed98ba" xlink:to="loc_us-gaap_GoodFaithAndMarginDepositsWithBrokerDealers_9cf803a4-d1c5-44de-a16c-9f2c44890a69" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/PerformanceBondsandGuarantyFundContributionsPerformanceBondDepositsandSecurityDepositsDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#PerformanceBondsandGuarantyFundContributionsPerformanceBondDepositsandSecurityDepositsDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/PerformanceBondsandGuarantyFundContributionsPerformanceBondDepositsandSecurityDepositsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_29a2920b-ffeb-41bf-a82e-40dc6c4c5746" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_f4e83c68-db21-41aa-b204-2f0393213a5d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_29a2920b-ffeb-41bf-a82e-40dc6c4c5746" xlink:to="loc_us-gaap_StatementTable_f4e83c68-db21-41aa-b204-2f0393213a5d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsByNatureAxis_39f02e66-3aee-494c-b316-12a97db620de" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GuaranteeObligationsByNatureAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_f4e83c68-db21-41aa-b204-2f0393213a5d" xlink:to="loc_us-gaap_GuaranteeObligationsByNatureAxis_39f02e66-3aee-494c-b316-12a97db620de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_39f02e66-3aee-494c-b316-12a97db620de_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_39f02e66-3aee-494c-b316-12a97db620de" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_39f02e66-3aee-494c-b316-12a97db620de_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_57105dc5-e6ed-47b8-a439-18764facce17" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_39f02e66-3aee-494c-b316-12a97db620de" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_57105dc5-e6ed-47b8-a439-18764facce17" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_PerformanceBondMember_7bfad650-a2c2-472b-a77a-21a51c373946" xlink:href="cme-20231231.xsd#cme_PerformanceBondMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_57105dc5-e6ed-47b8-a439-18764facce17" xlink:to="loc_cme_PerformanceBondMember_7bfad650-a2c2-472b-a77a-21a51c373946" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_DeliveryMember_81679b5c-53d6-47c2-96c5-6c651347553f" xlink:href="cme-20231231.xsd#cme_DeliveryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_57105dc5-e6ed-47b8-a439-18764facce17" xlink:to="loc_cme_DeliveryMember_81679b5c-53d6-47c2-96c5-6c651347553f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_f35f1ecd-cc7d-4bd6-a26c-8672ddeefc5e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_29a2920b-ffeb-41bf-a82e-40dc6c4c5746" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_f35f1ecd-cc7d-4bd6-a26c-8672ddeefc5e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/PropertyDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#PropertyDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/PropertyDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_b3b75154-ce02-4beb-9735-4b5b15446097" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_ac0c3560-bbcf-4403-be3e-a681260a8507" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_b3b75154-ce02-4beb-9735-4b5b15446097" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_ac0c3560-bbcf-4403-be3e-a681260a8507" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_e95fb31e-a0c8-4bad-9bd7-6b6a92178f13" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_ac0c3560-bbcf-4403-be3e-a681260a8507" xlink:to="loc_srt_RangeAxis_e95fb31e-a0c8-4bad-9bd7-6b6a92178f13" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e95fb31e-a0c8-4bad-9bd7-6b6a92178f13_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_e95fb31e-a0c8-4bad-9bd7-6b6a92178f13" xlink:to="loc_srt_RangeMember_e95fb31e-a0c8-4bad-9bd7-6b6a92178f13_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_8026334b-c7b9-42c2-9aa6-708e222d730c" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_e95fb31e-a0c8-4bad-9bd7-6b6a92178f13" xlink:to="loc_srt_RangeMember_8026334b-c7b9-42c2-9aa6-708e222d730c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_32b4c6f4-b667-4835-bf24-9994f0a725e4" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_8026334b-c7b9-42c2-9aa6-708e222d730c" xlink:to="loc_srt_MinimumMember_32b4c6f4-b667-4835-bf24-9994f0a725e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_7750f645-99d0-47ea-aeaf-ea2078fb19e3" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_8026334b-c7b9-42c2-9aa6-708e222d730c" xlink:to="loc_srt_MaximumMember_7750f645-99d0-47ea-aeaf-ea2078fb19e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_7738aeb3-4dad-4600-becb-a08cb9350cf6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_ac0c3560-bbcf-4403-be3e-a681260a8507" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_7738aeb3-4dad-4600-becb-a08cb9350cf6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7738aeb3-4dad-4600-becb-a08cb9350cf6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_7738aeb3-4dad-4600-becb-a08cb9350cf6" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_7738aeb3-4dad-4600-becb-a08cb9350cf6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_218ca1c3-a735-4393-a2f9-c9c994da0810" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_7738aeb3-4dad-4600-becb-a08cb9350cf6" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_218ca1c3-a735-4393-a2f9-c9c994da0810" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_bcbedbd5-1f20-428f-9b0e-5cc87a475170" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SoftwareAndSoftwareDevelopmentCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_218ca1c3-a735-4393-a2f9-c9c994da0810" xlink:to="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_bcbedbd5-1f20-428f-9b0e-5cc87a475170" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_41010cb2-4bf6-42a4-baca-68433883ea66" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_218ca1c3-a735-4393-a2f9-c9c994da0810" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_41010cb2-4bf6-42a4-baca-68433883ea66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_e70fb36a-cd1f-4486-bd29-e0c5d4295380" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_218ca1c3-a735-4393-a2f9-c9c994da0810" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_e70fb36a-cd1f-4486-bd29-e0c5d4295380" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_571bb004-62be-4804-9ef4-d4a05616ab78" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_218ca1c3-a735-4393-a2f9-c9c994da0810" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_571bb004-62be-4804-9ef4-d4a05616ab78" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_34707bf8-dcad-486e-8c1d-4c143abbbd6b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_b3b75154-ce02-4beb-9735-4b5b15446097" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_34707bf8-dcad-486e-8c1d-4c143abbbd6b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_8fe0bafe-89ed-4e9e-964b-ffe531cfb691" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_b3b75154-ce02-4beb-9735-4b5b15446097" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_8fe0bafe-89ed-4e9e-964b-ffe531cfb691" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_f9a13364-e42a-4791-be63-f07f84d94ddb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_b3b75154-ce02-4beb-9735-4b5b15446097" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_f9a13364-e42a-4791-be63-f07f84d94ddb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_e35c2c56-c366-464b-903e-8db04fe0498a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_b3b75154-ce02-4beb-9735-4b5b15446097" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_e35c2c56-c366-464b-903e-8db04fe0498a" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/IntangibleAssetsandGoodwillNarrativeDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#IntangibleAssetsandGoodwillNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/IntangibleAssetsandGoodwillNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_c56c00bb-4f6b-4034-8896-cc4c1273226f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_9c2d82b2-9937-49b7-96b0-01a3ea4861f8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_c56c00bb-4f6b-4034-8896-cc4c1273226f" xlink:to="loc_us-gaap_StatementTable_9c2d82b2-9937-49b7-96b0-01a3ea4861f8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_b8e903fd-302b-484b-8cec-44d93a0cf0da" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9c2d82b2-9937-49b7-96b0-01a3ea4861f8" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_b8e903fd-302b-484b-8cec-44d93a0cf0da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_b8e903fd-302b-484b-8cec-44d93a0cf0da_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_b8e903fd-302b-484b-8cec-44d93a0cf0da" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_b8e903fd-302b-484b-8cec-44d93a0cf0da_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_8e26ee45-9d25-411d-9e4b-88e2f3b27a66" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_b8e903fd-302b-484b-8cec-44d93a0cf0da" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_8e26ee45-9d25-411d-9e4b-88e2f3b27a66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_c9909127-83e0-493a-b1c9-8b5af80b94ea" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9c2d82b2-9937-49b7-96b0-01a3ea4861f8" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_c9909127-83e0-493a-b1c9-8b5af80b94ea" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_c9909127-83e0-493a-b1c9-8b5af80b94ea_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_c9909127-83e0-493a-b1c9-8b5af80b94ea" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_c9909127-83e0-493a-b1c9-8b5af80b94ea_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_21d6f316-f853-4a61-81de-65da17598594" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_c9909127-83e0-493a-b1c9-8b5af80b94ea" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_21d6f316-f853-4a61-81de-65da17598594" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_4dbc4109-b9c3-4547-b606-0a2f54584c19" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c56c00bb-4f6b-4034-8896-cc4c1273226f" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_4dbc4109-b9c3-4547-b606-0a2f54584c19" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_55efe24f-e0d4-49de-a28c-366e036b5ce6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c56c00bb-4f6b-4034-8896-cc4c1273226f" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_55efe24f-e0d4-49de-a28c-366e036b5ce6" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/IntangibleAssetsandGoodwillComponentsofIntangibleAssetsDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#IntangibleAssetsandGoodwillComponentsofIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/IntangibleAssetsandGoodwillComponentsofIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_c9193d6c-7cd0-4368-bc96-41d2a23c4ba3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_583395c1-a0d9-4175-89ad-3ca746b62d16" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_c9193d6c-7cd0-4368-bc96-41d2a23c4ba3" xlink:to="loc_us-gaap_StatementTable_583395c1-a0d9-4175-89ad-3ca746b62d16" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_ef2aa372-fa40-4774-9503-d42b75688bec" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_583395c1-a0d9-4175-89ad-3ca746b62d16" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_ef2aa372-fa40-4774-9503-d42b75688bec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ef2aa372-fa40-4774-9503-d42b75688bec_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_ef2aa372-fa40-4774-9503-d42b75688bec" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ef2aa372-fa40-4774-9503-d42b75688bec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a8aebab4-7a2c-47ae-a0cc-4c8859984d24" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_ef2aa372-fa40-4774-9503-d42b75688bec" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a8aebab4-7a2c-47ae-a0cc-4c8859984d24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_7385df89-e02b-4b54-a51d-44750f078feb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a8aebab4-7a2c-47ae-a0cc-4c8859984d24" xlink:to="loc_us-gaap_CustomerRelationshipsMember_7385df89-e02b-4b54-a51d-44750f078feb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_59fbeb12-1a81-4959-8b5e-76bb1866bae1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a8aebab4-7a2c-47ae-a0cc-4c8859984d24" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_59fbeb12-1a81-4959-8b5e-76bb1866bae1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_386f8bd8-95e9-49ba-a6f5-55387705220a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a8aebab4-7a2c-47ae-a0cc-4c8859984d24" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_386f8bd8-95e9-49ba-a6f5-55387705220a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMember_b77e40ad-dd9e-44d7-91d7-e74fb1018b3e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a8aebab4-7a2c-47ae-a0cc-4c8859984d24" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMember_b77e40ad-dd9e-44d7-91d7-e74fb1018b3e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_f103f2e9-2142-4572-b310-3e01d50d9574" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_583395c1-a0d9-4175-89ad-3ca746b62d16" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_f103f2e9-2142-4572-b310-3e01d50d9574" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_f103f2e9-2142-4572-b310-3e01d50d9574_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_f103f2e9-2142-4572-b310-3e01d50d9574" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_f103f2e9-2142-4572-b310-3e01d50d9574_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_d2d3a1a8-6a60-4900-aade-39396486aa07" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_f103f2e9-2142-4572-b310-3e01d50d9574" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_d2d3a1a8-6a60-4900-aade-39396486aa07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeNamesMember_b324a68e-4bc8-4f86-b32e-aa09ff1dd72d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_d2d3a1a8-6a60-4900-aade-39396486aa07" xlink:to="loc_us-gaap_TradeNamesMember_b324a68e-4bc8-4f86-b32e-aa09ff1dd72d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_39a2bb4d-4022-444f-a381-0f423ab9a51f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c9193d6c-7cd0-4368-bc96-41d2a23c4ba3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_39a2bb4d-4022-444f-a381-0f423ab9a51f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_1308c435-a2a4-47b5-b222-552a318a64c9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c9193d6c-7cd0-4368-bc96-41d2a23c4ba3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_1308c435-a2a4-47b5-b222-552a318a64c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_166b629e-f30e-4f4e-ad31-5cda6ef2f642" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c9193d6c-7cd0-4368-bc96-41d2a23c4ba3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_166b629e-f30e-4f4e-ad31-5cda6ef2f642" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIndefiniteLivedIntangibleAssets_3a12d043-4dde-40eb-9b30-ef5f48163e26" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherIndefiniteLivedIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c9193d6c-7cd0-4368-bc96-41d2a23c4ba3" xlink:to="loc_us-gaap_OtherIndefiniteLivedIntangibleAssets_3a12d043-4dde-40eb-9b30-ef5f48163e26" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/IntangibleAssetsandGoodwillIntangibleAssetsandGoodwillUsefulLivesofIntangibleAssetsDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#IntangibleAssetsandGoodwillIntangibleAssetsandGoodwillUsefulLivesofIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/IntangibleAssetsandGoodwillIntangibleAssetsandGoodwillUsefulLivesofIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_733b1658-cd65-4561-acb7-739fb6eda450" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a4bae6ff-ada6-4d4b-8f8b-79edefd2d375" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_733b1658-cd65-4561-acb7-739fb6eda450" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a4bae6ff-ada6-4d4b-8f8b-79edefd2d375" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_ebe0ef0b-96bf-4a98-bf73-2483a24b8ca8" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a4bae6ff-ada6-4d4b-8f8b-79edefd2d375" xlink:to="loc_srt_RangeAxis_ebe0ef0b-96bf-4a98-bf73-2483a24b8ca8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_ebe0ef0b-96bf-4a98-bf73-2483a24b8ca8_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_ebe0ef0b-96bf-4a98-bf73-2483a24b8ca8" xlink:to="loc_srt_RangeMember_ebe0ef0b-96bf-4a98-bf73-2483a24b8ca8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_3b92a8e4-b472-4f84-8a5e-178107584451" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_ebe0ef0b-96bf-4a98-bf73-2483a24b8ca8" xlink:to="loc_srt_RangeMember_3b92a8e4-b472-4f84-8a5e-178107584451" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_0dfafdb5-5e4f-4df1-a38b-17c552f0208b" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3b92a8e4-b472-4f84-8a5e-178107584451" xlink:to="loc_srt_MinimumMember_0dfafdb5-5e4f-4df1-a38b-17c552f0208b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_a7ac3d4b-9d4f-4997-a9c8-2de4d261a392" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3b92a8e4-b472-4f84-8a5e-178107584451" xlink:to="loc_srt_MaximumMember_a7ac3d4b-9d4f-4997-a9c8-2de4d261a392" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_8d2baefe-b757-4948-ad39-e0c3d976d506" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a4bae6ff-ada6-4d4b-8f8b-79edefd2d375" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_8d2baefe-b757-4948-ad39-e0c3d976d506" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_8d2baefe-b757-4948-ad39-e0c3d976d506_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_8d2baefe-b757-4948-ad39-e0c3d976d506" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_8d2baefe-b757-4948-ad39-e0c3d976d506_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_1910eff5-376a-447d-b1bd-47cfd9c74e62" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_8d2baefe-b757-4948-ad39-e0c3d976d506" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_1910eff5-376a-447d-b1bd-47cfd9c74e62" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_66c9d718-abcb-4531-9070-6b2bac6a937b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_1910eff5-376a-447d-b1bd-47cfd9c74e62" xlink:to="loc_us-gaap_CustomerRelationshipsMember_66c9d718-abcb-4531-9070-6b2bac6a937b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_33d2aaef-e559-48b5-8f17-9c7e0a3109e1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_1910eff5-376a-447d-b1bd-47cfd9c74e62" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_33d2aaef-e559-48b5-8f17-9c7e0a3109e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_9509434f-4ff0-464f-8380-0b2f99f0fd72" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_1910eff5-376a-447d-b1bd-47cfd9c74e62" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_9509434f-4ff0-464f-8380-0b2f99f0fd72" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_71c4c17a-b0af-4e62-9aeb-462f59b9bf20" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_733b1658-cd65-4561-acb7-739fb6eda450" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_71c4c17a-b0af-4e62-9aeb-462f59b9bf20" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/IntangibleAssetsandGoodwillIntangibleAssetsandGoodwillComponentsofGoodwillDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#IntangibleAssetsandGoodwillIntangibleAssetsandGoodwillComponentsofGoodwillDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/IntangibleAssetsandGoodwillIntangibleAssetsandGoodwillComponentsofGoodwillDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_cd860a62-46ab-40aa-bf78-3d920e37028c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_6ffd5a68-3ddc-41c9-a34f-1d2f14917ec3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_cd860a62-46ab-40aa-bf78-3d920e37028c" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_6ffd5a68-3ddc-41c9-a34f-1d2f14917ec3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_84500ec0-0ba4-4f0c-82d5-de796a9851a5" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_6ffd5a68-3ddc-41c9-a34f-1d2f14917ec3" xlink:to="loc_srt_ConsolidationItemsAxis_84500ec0-0ba4-4f0c-82d5-de796a9851a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_84500ec0-0ba4-4f0c-82d5-de796a9851a5_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_84500ec0-0ba4-4f0c-82d5-de796a9851a5" xlink:to="loc_srt_ConsolidationItemsDomain_84500ec0-0ba4-4f0c-82d5-de796a9851a5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_e8749b4b-9cdd-442a-961f-7269e627c2bb" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_84500ec0-0ba4-4f0c-82d5-de796a9851a5" xlink:to="loc_srt_ConsolidationItemsDomain_e8749b4b-9cdd-442a-961f-7269e627c2bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_d6c66d60-9cb1-4652-a942-cd0487318420" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_6ffd5a68-3ddc-41c9-a34f-1d2f14917ec3" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_d6c66d60-9cb1-4652-a942-cd0487318420" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_d6c66d60-9cb1-4652-a942-cd0487318420_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_d6c66d60-9cb1-4652-a942-cd0487318420" xlink:to="loc_us-gaap_SegmentDomain_d6c66d60-9cb1-4652-a942-cd0487318420_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_460cefa6-7245-45ff-8794-5ae1b9406789" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_d6c66d60-9cb1-4652-a942-cd0487318420" xlink:to="loc_us-gaap_SegmentDomain_460cefa6-7245-45ff-8794-5ae1b9406789" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_CBOTMember_47017f53-d327-45f0-a97d-484754867dc9" xlink:href="cme-20231231.xsd#cme_CBOTMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_460cefa6-7245-45ff-8794-5ae1b9406789" xlink:to="loc_cme_CBOTMember_47017f53-d327-45f0-a97d-484754867dc9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_NymexMember_d06ee03e-623b-4ac3-8a08-a2ee31f68776" xlink:href="cme-20231231.xsd#cme_NymexMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_460cefa6-7245-45ff-8794-5ae1b9406789" xlink:to="loc_cme_NymexMember_d06ee03e-623b-4ac3-8a08-a2ee31f68776" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_NEXMember_b2465c9e-a409-4f07-bcdd-89e37e0b6179" xlink:href="cme-20231231.xsd#cme_NEXMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_460cefa6-7245-45ff-8794-5ae1b9406789" xlink:to="loc_cme_NEXMember_b2465c9e-a409-4f07-bcdd-89e37e0b6179" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_OtherCMESegmentsMember_ed8262b9-6718-49d3-b0e6-5a282933babc" xlink:href="cme-20231231.xsd#cme_OtherCMESegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_460cefa6-7245-45ff-8794-5ae1b9406789" xlink:to="loc_cme_OtherCMESegmentsMember_ed8262b9-6718-49d3-b0e6-5a282933babc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_CMEGroupIncMember_e9a46d23-f219-454c-84c1-8fde00733492" xlink:href="cme-20231231.xsd#cme_CMEGroupIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_460cefa6-7245-45ff-8794-5ae1b9406789" xlink:to="loc_cme_CMEGroupIncMember_e9a46d23-f219-454c-84c1-8fde00733492" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_1ec170c1-f3dd-4b3b-ba66-aa81e7e7150c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_6ffd5a68-3ddc-41c9-a34f-1d2f14917ec3" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_1ec170c1-f3dd-4b3b-ba66-aa81e7e7150c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_1ec170c1-f3dd-4b3b-ba66-aa81e7e7150c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_1ec170c1-f3dd-4b3b-ba66-aa81e7e7150c" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_1ec170c1-f3dd-4b3b-ba66-aa81e7e7150c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_ec63184f-b063-4007-9bde-b5aea2b7d853" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_1ec170c1-f3dd-4b3b-ba66-aa81e7e7150c" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_ec63184f-b063-4007-9bde-b5aea2b7d853" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_c067e5f8-072b-4b9f-88d3-7827f13b405f" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_6ffd5a68-3ddc-41c9-a34f-1d2f14917ec3" xlink:to="loc_srt_RangeAxis_c067e5f8-072b-4b9f-88d3-7827f13b405f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_c067e5f8-072b-4b9f-88d3-7827f13b405f_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_c067e5f8-072b-4b9f-88d3-7827f13b405f" xlink:to="loc_srt_RangeMember_c067e5f8-072b-4b9f-88d3-7827f13b405f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_13090f98-9ad0-426c-8d9e-8eb64e1e0510" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_c067e5f8-072b-4b9f-88d3-7827f13b405f" xlink:to="loc_srt_RangeMember_13090f98-9ad0-426c-8d9e-8eb64e1e0510" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitAxis_567d77bd-46b1-4e8e-9326-13a66225db23" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReportingUnitAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_6ffd5a68-3ddc-41c9-a34f-1d2f14917ec3" xlink:to="loc_us-gaap_ReportingUnitAxis_567d77bd-46b1-4e8e-9326-13a66225db23" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitDomain_567d77bd-46b1-4e8e-9326-13a66225db23_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReportingUnitDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReportingUnitAxis_567d77bd-46b1-4e8e-9326-13a66225db23" xlink:to="loc_us-gaap_ReportingUnitDomain_567d77bd-46b1-4e8e-9326-13a66225db23_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitDomain_9002a10a-3c4f-4850-84d5-5c9cfaac7661" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReportingUnitDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReportingUnitAxis_567d77bd-46b1-4e8e-9326-13a66225db23" xlink:to="loc_us-gaap_ReportingUnitDomain_9002a10a-3c4f-4850-84d5-5c9cfaac7661" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_8268b2d8-46ee-49b1-b2c9-6678aa0ad139" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_cd860a62-46ab-40aa-bf78-3d920e37028c" xlink:to="loc_us-gaap_Goodwill_8268b2d8-46ee-49b1-b2c9-6678aa0ad139" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillOtherIncreaseDecrease_241aa30a-a8e3-4c21-92b7-8c8523789509" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillOtherIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_cd860a62-46ab-40aa-bf78-3d920e37028c" xlink:to="loc_us-gaap_GoodwillOtherIncreaseDecrease_241aa30a-a8e3-4c21-92b7-8c8523789509" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/LongTermInvestmentsDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#LongTermInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/LongTermInvestmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_d61eed63-b45c-4627-b2f3-0d0ea90de288" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_363be4c7-74db-4631-9455-4ac82b6529b1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_d61eed63-b45c-4627-b2f3-0d0ea90de288" xlink:to="loc_us-gaap_StatementTable_363be4c7-74db-4631-9455-4ac82b6529b1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_59e9ccac-1d2f-4ab0-871f-8b277b83714c" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_363be4c7-74db-4631-9455-4ac82b6529b1" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_59e9ccac-1d2f-4ab0-871f-8b277b83714c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_59e9ccac-1d2f-4ab0-871f-8b277b83714c_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_59e9ccac-1d2f-4ab0-871f-8b277b83714c" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_59e9ccac-1d2f-4ab0-871f-8b277b83714c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_0bea3200-5d5a-4878-b80e-4028bd902930" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_59e9ccac-1d2f-4ab0-871f-8b277b83714c" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_0bea3200-5d5a-4878-b80e-4028bd902930" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_DmeHoldingsMember_5abc3348-31db-4542-b9a0-c2aa7032c66d" xlink:href="cme-20231231.xsd#cme_DmeHoldingsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_0bea3200-5d5a-4878-b80e-4028bd902930" xlink:to="loc_cme_DmeHoldingsMember_5abc3348-31db-4542-b9a0-c2aa7032c66d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_OSSTRAMember_24718672-671a-4565-a640-f181633a3dba" xlink:href="cme-20231231.xsd#cme_OSSTRAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_0bea3200-5d5a-4878-b80e-4028bd902930" xlink:to="loc_cme_OSSTRAMember_24718672-671a-4565-a640-f181633a3dba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_SandpdjiMember_4c0a12fc-2b3a-4ff8-b253-7c49c6c2b7ef" xlink:href="cme-20231231.xsd#cme_SandpdjiMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_0bea3200-5d5a-4878-b80e-4028bd902930" xlink:to="loc_cme_SandpdjiMember_4c0a12fc-2b3a-4ff8-b253-7c49c6c2b7ef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_CFETSMember_125d5a5a-6579-4553-9fa4-3acb54a69d7a" xlink:href="cme-20231231.xsd#cme_CFETSMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_0bea3200-5d5a-4878-b80e-4028bd902930" xlink:to="loc_cme_CFETSMember_125d5a5a-6579-4553-9fa4-3acb54a69d7a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_2b316b89-bf1a-4ae9-988b-88d05b156252" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d61eed63-b45c-4627-b2f3-0d0ea90de288" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_2b316b89-bf1a-4ae9-988b-88d05b156252" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnInvestments_375f6eb9-5156-4b50-a8ab-eadbeade35f3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GainLossOnInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d61eed63-b45c-4627-b2f3-0d0ea90de288" xlink:to="loc_us-gaap_GainLossOnInvestments_375f6eb9-5156-4b50-a8ab-eadbeade35f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_c3532f48-35bc-4c50-8ee9-f170ef204a4b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d61eed63-b45c-4627-b2f3-0d0ea90de288" xlink:to="loc_us-gaap_EquityMethodInvestments_c3532f48-35bc-4c50-8ee9-f170ef204a4b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfBusinessesAndInterestsInAffiliates_4a90909c-b6fd-46e1-943a-3a481315adfa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromDivestitureOfBusinessesAndInterestsInAffiliates"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d61eed63-b45c-4627-b2f3-0d0ea90de288" xlink:to="loc_us-gaap_ProceedsFromDivestitureOfBusinessesAndInterestsInAffiliates_4a90909c-b6fd-46e1-943a-3a481315adfa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeconsolidationGainOrLossAmount_6e3506af-8bf5-4a1d-92e0-7ec2dd6e2313" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeconsolidationGainOrLossAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d61eed63-b45c-4627-b2f3-0d0ea90de288" xlink:to="loc_us-gaap_DeconsolidationGainOrLossAmount_6e3506af-8bf5-4a1d-92e0-7ec2dd6e2313" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireInvestments_84cb3ec6-3401-4b91-ad0d-7793bd566365" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsToAcquireInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d61eed63-b45c-4627-b2f3-0d0ea90de288" xlink:to="loc_us-gaap_PaymentsToAcquireInvestments_84cb3ec6-3401-4b91-ad0d-7793bd566365" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/DebtScheduleofShortTermandLongTermDebtDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#DebtScheduleofShortTermandLongTermDebtDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/DebtScheduleofShortTermandLongTermDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_cd31e740-a2d8-4df6-b2c9-8686502da48d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_c6b8f1a1-5fc6-4dfc-813a-2c7b661917d9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_cd31e740-a2d8-4df6-b2c9-8686502da48d" xlink:to="loc_us-gaap_StatementTable_c6b8f1a1-5fc6-4dfc-813a-2c7b661917d9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_129cceb4-1b79-4522-b77a-0a182e107633" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_c6b8f1a1-5fc6-4dfc-813a-2c7b661917d9" xlink:to="loc_us-gaap_DebtInstrumentAxis_129cceb4-1b79-4522-b77a-0a182e107633" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_129cceb4-1b79-4522-b77a-0a182e107633_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_129cceb4-1b79-4522-b77a-0a182e107633" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_129cceb4-1b79-4522-b77a-0a182e107633_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_5332ccf7-8692-42d2-8d83-dfc30363c382" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_129cceb4-1b79-4522-b77a-0a182e107633" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_5332ccf7-8692-42d2-8d83-dfc30363c382" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_A750.0millionFixedRateNotesDueSeptember2022InterestEqualTo3.00Member_064569e0-2619-41f5-9482-ae89f5cefdf3" xlink:href="cme-20231231.xsd#cme_A750.0millionFixedRateNotesDueSeptember2022InterestEqualTo3.00Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_5332ccf7-8692-42d2-8d83-dfc30363c382" xlink:to="loc_cme_A750.0millionFixedRateNotesDueSeptember2022InterestEqualTo3.00Member_064569e0-2619-41f5-9482-ae89f5cefdf3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_A15.0millionfixedratenotesdueMay2023Member_1f6e6e9a-1a0c-4c2f-8613-b62e927edf42" xlink:href="cme-20231231.xsd#cme_A15.0millionfixedratenotesdueMay2023Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_5332ccf7-8692-42d2-8d83-dfc30363c382" xlink:to="loc_cme_A15.0millionfixedratenotesdueMay2023Member_1f6e6e9a-1a0c-4c2f-8613-b62e927edf42" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_A750.0MillionFixedRateNotesDueMarch2025InterestEqualTo3.00Member_9aec5496-5248-401d-a7cc-2e151eba7673" xlink:href="cme-20231231.xsd#cme_A750.0MillionFixedRateNotesDueMarch2025InterestEqualTo3.00Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_5332ccf7-8692-42d2-8d83-dfc30363c382" xlink:to="loc_cme_A750.0MillionFixedRateNotesDueMarch2025InterestEqualTo3.00Member_9aec5496-5248-401d-a7cc-2e151eba7673" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_A500.0MillionFixedRateNotesDueJune2028InterestEqualTo3.75MemberDomain_7f943d40-06c3-41e4-957d-09e227820a7c" xlink:href="cme-20231231.xsd#cme_A500.0MillionFixedRateNotesDueJune2028InterestEqualTo3.75MemberDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_5332ccf7-8692-42d2-8d83-dfc30363c382" xlink:to="loc_cme_A500.0MillionFixedRateNotesDueJune2028InterestEqualTo3.75MemberDomain_7f943d40-06c3-41e4-957d-09e227820a7c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_A750.0millionFixedRateNotesDueSeptember2043InterestEqualTo5.3Member_38c2d88f-8bae-4e44-8980-71c53b3005ee" xlink:href="cme-20231231.xsd#cme_A750.0millionFixedRateNotesDueSeptember2043InterestEqualTo5.3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_5332ccf7-8692-42d2-8d83-dfc30363c382" xlink:to="loc_cme_A750.0millionFixedRateNotesDueSeptember2043InterestEqualTo5.3Member_38c2d88f-8bae-4e44-8980-71c53b3005ee" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_A700.0MillionFixedRateNotesDueJune2048InterestEqualTo4.15MemberDomainDomain_fb4a9976-acf9-4cc2-a1f2-cda59f5f7439" xlink:href="cme-20231231.xsd#cme_A700.0MillionFixedRateNotesDueJune2048InterestEqualTo4.15MemberDomainDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_5332ccf7-8692-42d2-8d83-dfc30363c382" xlink:to="loc_cme_A700.0MillionFixedRateNotesDueJune2048InterestEqualTo4.15MemberDomainDomain_fb4a9976-acf9-4cc2-a1f2-cda59f5f7439" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_A7500MillionFixedRateNotesDueMarch2032InterestEqualTo265Member_60a75400-05c4-439b-ab58-4c15abd099f7" xlink:href="cme-20231231.xsd#cme_A7500MillionFixedRateNotesDueMarch2032InterestEqualTo265Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_5332ccf7-8692-42d2-8d83-dfc30363c382" xlink:to="loc_cme_A7500MillionFixedRateNotesDueMarch2032InterestEqualTo265Member_60a75400-05c4-439b-ab58-4c15abd099f7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_e21b7559-bee0-40d6-9f21-fba68066b402" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtCurrentAndNoncurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_cd31e740-a2d8-4df6-b2c9-8686502da48d" xlink:to="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_e21b7559-bee0-40d6-9f21-fba68066b402" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnsecuredLongTermDebt_9076b3fd-10c6-451e-9d27-7feb8df6634b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnsecuredLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_e21b7559-bee0-40d6-9f21-fba68066b402" xlink:to="loc_us-gaap_UnsecuredLongTermDebt_9076b3fd-10c6-451e-9d27-7feb8df6634b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_cd9cf212-aac7-4fd0-a39e-f15948c318a3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_e21b7559-bee0-40d6-9f21-fba68066b402" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_cd9cf212-aac7-4fd0-a39e-f15948c318a3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentMaturityDate_8d29aad1-e80d-4389-b61c-e1ee5996bc85" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentMaturityDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_e21b7559-bee0-40d6-9f21-fba68066b402" xlink:to="loc_us-gaap_DebtInstrumentMaturityDate_8d29aad1-e80d-4389-b61c-e1ee5996bc85" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_4eeef5c1-6621-4ee2-b127-e901fb4f1519" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtCurrentAndNoncurrentAbstract_e21b7559-bee0-40d6-9f21-fba68066b402" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_4eeef5c1-6621-4ee2-b127-e901fb4f1519" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateDuringPeriod_0af17a9d-4e75-421a-8f44-df8a0aef8ca0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_cd31e740-a2d8-4df6-b2c9-8686502da48d" xlink:to="loc_us-gaap_DebtInstrumentInterestRateDuringPeriod_0af17a9d-4e75-421a-8f44-df8a0aef8ca0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_3febd906-df10-4347-8741-ccbb2542032e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_cd31e740-a2d8-4df6-b2c9-8686502da48d" xlink:to="loc_us-gaap_ShortTermBorrowings_3febd906-df10-4347-8741-ccbb2542032e" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/IncomeTaxesDeferredTaxAssetsLiabilitiesDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#IncomeTaxesDeferredTaxAssetsLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/IncomeTaxesDeferredTaxAssetsLiabilitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_8a7424c5-a4fd-4efd-9f06-08f2bd50072c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_0df091bd-7d99-4743-bd4e-b65bb4d41591" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_8a7424c5-a4fd-4efd-9f06-08f2bd50072c" xlink:to="loc_us-gaap_StatementTable_0df091bd-7d99-4743-bd4e-b65bb4d41591" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_92122cc9-b584-40bd-a33e-befb89de561c" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0df091bd-7d99-4743-bd4e-b65bb4d41591" xlink:to="loc_srt_StatementScenarioAxis_92122cc9-b584-40bd-a33e-befb89de561c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_92122cc9-b584-40bd-a33e-befb89de561c_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_92122cc9-b584-40bd-a33e-befb89de561c" xlink:to="loc_srt_ScenarioUnspecifiedDomain_92122cc9-b584-40bd-a33e-befb89de561c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_9f31551a-e2ca-42c9-8e0d-3c5db5849447" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_92122cc9-b584-40bd-a33e-befb89de561c" xlink:to="loc_srt_ScenarioUnspecifiedDomain_9f31551a-e2ca-42c9-8e0d-3c5db5849447" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_28843eca-5555-4a88-9a0b-9318c6975a25" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8a7424c5-a4fd-4efd-9f06-08f2bd50072c" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_28843eca-5555-4a88-9a0b-9318c6975a25" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsOther_0305a7c3-c167-428c-9bae-c826a6971b48" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8a7424c5-a4fd-4efd-9f06-08f2bd50072c" xlink:to="loc_us-gaap_DeferredTaxAssetsOther_0305a7c3-c167-428c-9bae-c826a6971b48" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsGross_94c7a796-627e-4d9c-9530-b7e016f5e0ad" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8a7424c5-a4fd-4efd-9f06-08f2bd50072c" xlink:to="loc_us-gaap_DeferredTaxAssetsGross_94c7a796-627e-4d9c-9530-b7e016f5e0ad" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsValuationAllowance_b1fc2d7d-0167-45ba-bfb4-98596745d297" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsValuationAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8a7424c5-a4fd-4efd-9f06-08f2bd50072c" xlink:to="loc_us-gaap_DeferredTaxAssetsValuationAllowance_b1fc2d7d-0167-45ba-bfb4-98596745d297" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsNet_5cceb3ad-a89d-4131-957f-82a810986af9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8a7424c5-a4fd-4efd-9f06-08f2bd50072c" xlink:to="loc_us-gaap_DeferredTaxAssetsNet_5cceb3ad-a89d-4131-957f-82a810986af9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssets_aa0ae299-a8f1-4a94-80e3-ea3a2da72277" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8a7424c5-a4fd-4efd-9f06-08f2bd50072c" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssets_aa0ae299-a8f1-4a94-80e3-ea3a2da72277" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesOther_2957b807-f73d-4e66-8074-31cbccaf54ef" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxLiabilitiesOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8a7424c5-a4fd-4efd-9f06-08f2bd50072c" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesOther_2957b807-f73d-4e66-8074-31cbccaf54ef" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment_faf08a9b-2612-40dd-8128-2d52e8b7908a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8a7424c5-a4fd-4efd-9f06-08f2bd50072c" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment_faf08a9b-2612-40dd-8128-2d52e8b7908a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilities_02485c27-9708-41e1-a98b-2df766464f81" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8a7424c5-a4fd-4efd-9f06-08f2bd50072c" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilities_02485c27-9708-41e1-a98b-2df766464f81" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilities_9a7fa35f-bde3-4fb3-adfd-455994b9714e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8a7424c5-a4fd-4efd-9f06-08f2bd50072c" xlink:to="loc_us-gaap_DeferredTaxLiabilities_9a7fa35f-bde3-4fb3-adfd-455994b9714e" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsLiabilitiesNet_0b047d80-96d3-4e32-8b88-c7106a45813e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8a7424c5-a4fd-4efd-9f06-08f2bd50072c" xlink:to="loc_us-gaap_DeferredTaxAssetsLiabilitiesNet_0b047d80-96d3-4e32-8b88-c7106a45813e" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/IncomeTaxesIncomeTaxesNarrativeDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#IncomeTaxesIncomeTaxesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/IncomeTaxesIncomeTaxesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_99b960c6-f55f-4a6c-8bf0-db80883382fa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_0f6401fb-d0eb-490e-b628-ea08f3f2f042" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_99b960c6-f55f-4a6c-8bf0-db80883382fa" xlink:to="loc_us-gaap_StatementTable_0f6401fb-d0eb-490e-b628-ea08f3f2f042" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_34d63354-bc54-4c20-8e18-a5aa6b267d4f" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0f6401fb-d0eb-490e-b628-ea08f3f2f042" xlink:to="loc_dei_LegalEntityAxis_34d63354-bc54-4c20-8e18-a5aa6b267d4f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_34d63354-bc54-4c20-8e18-a5aa6b267d4f_default" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_34d63354-bc54-4c20-8e18-a5aa6b267d4f" xlink:to="loc_dei_EntityDomain_34d63354-bc54-4c20-8e18-a5aa6b267d4f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_581ec8c5-43fc-41cf-86ff-5d2e236e009d" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_34d63354-bc54-4c20-8e18-a5aa6b267d4f" xlink:to="loc_dei_EntityDomain_581ec8c5-43fc-41cf-86ff-5d2e236e009d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards_cc84389d-26d4-4519-8db3-32bb14d8dbc4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLossCarryforwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_99b960c6-f55f-4a6c-8bf0-db80883382fa" xlink:to="loc_us-gaap_OperatingLossCarryforwards_cc84389d-26d4-4519-8db3-32bb14d8dbc4" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/EmployeeBenefitPlansNarrativeDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#EmployeeBenefitPlansNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/EmployeeBenefitPlansNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_a8f9e4e4-fb9b-420e-b1b8-b329f9674f78" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:to="loc_us-gaap_StatementTable_a8f9e4e4-fb9b-420e-b1b8-b329f9674f78" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_4c70a1f1-3051-40f4-a3c2-57abcbb3e2de" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_a8f9e4e4-fb9b-420e-b1b8-b329f9674f78" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_4c70a1f1-3051-40f4-a3c2-57abcbb3e2de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_4c70a1f1-3051-40f4-a3c2-57abcbb3e2de_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_4c70a1f1-3051-40f4-a3c2-57abcbb3e2de" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_4c70a1f1-3051-40f4-a3c2-57abcbb3e2de_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_fa387607-0225-46ac-82ec-d8e6240c5780" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_4c70a1f1-3051-40f4-a3c2-57abcbb3e2de" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_fa387607-0225-46ac-82ec-d8e6240c5780" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_5adcb630-073d-4620-920e-c2d423929aa3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_fa387607-0225-46ac-82ec-d8e6240c5780" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_5adcb630-073d-4620-920e-c2d423929aa3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_f815774d-1553-4c85-8b01-2e3ef45e02a3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_fa387607-0225-46ac-82ec-d8e6240c5780" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_f815774d-1553-4c85-8b01-2e3ef45e02a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_6631b025-61bc-4f82-8883-eb42d4d95bc2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_a8f9e4e4-fb9b-420e-b1b8-b329f9674f78" xlink:to="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_6631b025-61bc-4f82-8883-eb42d4d95bc2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_6631b025-61bc-4f82-8883-eb42d4d95bc2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_6631b025-61bc-4f82-8883-eb42d4d95bc2" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_6631b025-61bc-4f82-8883-eb42d4d95bc2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_1157f665-2357-495f-b309-d11cf1b48a53" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_6631b025-61bc-4f82-8883-eb42d4d95bc2" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_1157f665-2357-495f-b309-d11cf1b48a53" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDebtSecurityMember_e41796d4-a78f-4609-b56c-1532ce68060e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanDebtSecurityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_1157f665-2357-495f-b309-d11cf1b48a53" xlink:to="loc_us-gaap_DefinedBenefitPlanDebtSecurityMember_e41796d4-a78f-4609-b56c-1532ce68060e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember_e79c8f4c-b091-4209-9166-a64514a205cc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_1157f665-2357-495f-b309-d11cf1b48a53" xlink:to="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember_e79c8f4c-b091-4209-9166-a64514a205cc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember_98ad85ad-d930-4d67-87e4-f360da2e6e7c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_1157f665-2357-495f-b309-d11cf1b48a53" xlink:to="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember_98ad85ad-d930-4d67-87e4-f360da2e6e7c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_EligibleAgeToParticipateInBenefitPlan_29208f94-a466-40d7-96c2-77e32f25bdfc" xlink:href="cme-20231231.xsd#cme_EligibleAgeToParticipateInBenefitPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:to="loc_cme_EligibleAgeToParticipateInBenefitPlan_29208f94-a466-40d7-96c2-77e32f25bdfc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostCashBalanceInterestCreditingRate_e6662f85-6476-4c4b-a457-527a3738ec54" xlink:href="cme-20231231.xsd#cme_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostCashBalanceInterestCreditingRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:to="loc_cme_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostCashBalanceInterestCreditingRate_e6662f85-6476-4c4b-a457-527a3738ec54" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1_bff75536-a139-4098-af1d-5fdb7e43aa90" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1_bff75536-a139-4098-af1d-5fdb7e43aa90" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation_a993ae64-a47a-4d58-9944-a6052fa3cf48" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:to="loc_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation_a993ae64-a47a-4d58-9944-a6052fa3cf48" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_b986fd73-a2cf-4ae0-823e-8d1224e9f2bb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanFundedStatusOfPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:to="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_b986fd73-a2cf-4ae0-823e-8d1224e9f2bb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_0d1ab207-0f20-4023-a8f2-41c396d6a584" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:to="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_0d1ab207-0f20-4023-a8f2-41c396d6a584" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanCostRecognized_62592565-72df-4025-90f6-d24a4dde8fb7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedContributionPlanCostRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:to="loc_us-gaap_DefinedContributionPlanCostRecognized_62592565-72df-4025-90f6-d24a4dde8fb7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradingSecurities_fa9f502c-9468-46e9-b7cc-d17de6b8aa27" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TradingSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:to="loc_us-gaap_TradingSecurities_fa9f502c-9468-46e9-b7cc-d17de6b8aa27" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_FairValueOfAssetsUnderRetirementPlan_42ce31a2-ce9f-43fb-91c9-bbd75a704123" xlink:href="cme-20231231.xsd#cme_FairValueOfAssetsUnderRetirementPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:to="loc_cme_FairValueOfAssetsUnderRetirementPlan_42ce31a2-ce9f-43fb-91c9-bbd75a704123" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_bec74c2d-9d51-480c-ab6a-d4d33983e0ed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_bec74c2d-9d51-480c-ab6a-d4d33983e0ed" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_DefinedBenefitPlanFundingGoalPercentage_22fe597c-9b0d-45aa-8434-3b0e273f7e8e" xlink:href="cme-20231231.xsd#cme_DefinedBenefitPlanFundingGoalPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:to="loc_cme_DefinedBenefitPlanFundingGoalPercentage_22fe597c-9b0d-45aa-8434-3b0e273f7e8e" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_fafe85e1-86d9-465e-ac75-0f629dde70ad" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_fafe85e1-86d9-465e-ac75-0f629dde70ad" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_TotalObligation_3774556b-6d3d-404f-8999-ace2e5a670bc" xlink:href="cme-20231231.xsd#cme_TotalObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_60264faa-e6fe-4e56-a765-3dd3a0156a10" xlink:to="loc_cme_TotalObligation_3774556b-6d3d-404f-8999-ace2e5a670bc" xlink:type="arc" order="12"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/EmployeeBenefitPlansSummaryofthechangeinprojectedbenefitobligationDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#EmployeeBenefitPlansSummaryofthechangeinprojectedbenefitobligationDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/EmployeeBenefitPlansSummaryofthechangeinprojectedbenefitobligationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_c39bca18-1762-4900-a84a-d3001743de77" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_aaddd664-df8e-474c-a922-5fbaadaf903d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_c39bca18-1762-4900-a84a-d3001743de77" xlink:to="loc_us-gaap_StatementTable_aaddd664-df8e-474c-a922-5fbaadaf903d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_47e8faf9-26ed-4b92-a327-0e80b658c060" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_aaddd664-df8e-474c-a922-5fbaadaf903d" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_47e8faf9-26ed-4b92-a327-0e80b658c060" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_47e8faf9-26ed-4b92-a327-0e80b658c060_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_47e8faf9-26ed-4b92-a327-0e80b658c060" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_47e8faf9-26ed-4b92-a327-0e80b658c060_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_9d677ae8-99ff-405b-af80-e1ca7198dccf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_47e8faf9-26ed-4b92-a327-0e80b658c060" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_9d677ae8-99ff-405b-af80-e1ca7198dccf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_db21dff3-dfbb-49e3-a743-3ad0955e715d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_9d677ae8-99ff-405b-af80-e1ca7198dccf" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_db21dff3-dfbb-49e3-a743-3ad0955e715d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_b8238afb-2d09-41bf-bc3f-d7e41f7a5e35" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c39bca18-1762-4900-a84a-d3001743de77" xlink:to="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_b8238afb-2d09-41bf-bc3f-d7e41f7a5e35" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_a11cd986-2466-4967-9327-58e33e5f024f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_b8238afb-2d09-41bf-bc3f-d7e41f7a5e35" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligation_a11cd986-2466-4967-9327-58e33e5f024f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost_42ce1341-cc8e-48a6-b75e-d61503d8ec79" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_b8238afb-2d09-41bf-bc3f-d7e41f7a5e35" xlink:to="loc_us-gaap_DefinedBenefitPlanServiceCost_42ce1341-cc8e-48a6-b75e-d61503d8ec79" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_c5855f9e-b8b5-4c52-8a92-f3902b59725d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_b8238afb-2d09-41bf-bc3f-d7e41f7a5e35" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_c5855f9e-b8b5-4c52-8a92-f3902b59725d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_de725ea5-9408-4ee9-bb8d-5d9d7870c47e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanActuarialGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_b8238afb-2d09-41bf-bc3f-d7e41f7a5e35" xlink:to="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_de725ea5-9408-4ee9-bb8d-5d9d7870c47e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_5d02e608-d84e-47b2-b19a-85fa094a06bb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_b8238afb-2d09-41bf-bc3f-d7e41f7a5e35" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_5d02e608-d84e-47b2-b19a-85fa094a06bb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_76979ce3-729b-4140-8dd7-385f64016a1a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_b3564eda-101c-49d1-84f9-f8b59e26c407" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c39bca18-1762-4900-a84a-d3001743de77" xlink:to="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_b3564eda-101c-49d1-84f9-f8b59e26c407" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/EmployeeBenefitPlansChangeinPlanAssetsDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#EmployeeBenefitPlansChangeinPlanAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/EmployeeBenefitPlansChangeinPlanAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_56e56a6b-44e3-4c35-831a-45eaf052b180" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_646bbc90-89ed-4a5b-86fa-ee4acde4673b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_56e56a6b-44e3-4c35-831a-45eaf052b180" xlink:to="loc_us-gaap_StatementTable_646bbc90-89ed-4a5b-86fa-ee4acde4673b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_c070e973-7e25-4cef-aa4d-3694f91786d4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_646bbc90-89ed-4a5b-86fa-ee4acde4673b" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_c070e973-7e25-4cef-aa4d-3694f91786d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_c070e973-7e25-4cef-aa4d-3694f91786d4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_c070e973-7e25-4cef-aa4d-3694f91786d4" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_c070e973-7e25-4cef-aa4d-3694f91786d4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_53c79018-030b-4b90-814b-3d46c7673f9b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_c070e973-7e25-4cef-aa4d-3694f91786d4" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_53c79018-030b-4b90-814b-3d46c7673f9b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_33dcb591-b9ba-44da-b4f5-25cbfac859b5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_53c79018-030b-4b90-814b-3d46c7673f9b" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_33dcb591-b9ba-44da-b4f5-25cbfac859b5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_998d3e67-d11e-460b-9655-52472b5c3098" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_56e56a6b-44e3-4c35-831a-45eaf052b180" xlink:to="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_998d3e67-d11e-460b-9655-52472b5c3098" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_8eef9f7e-dadb-4241-8cbd-a760e32e6e49" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_998d3e67-d11e-460b-9655-52472b5c3098" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_8eef9f7e-dadb-4241-8cbd-a760e32e6e49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets_f3b65d55-6b0c-47e7-b3cb-139a901f5eec" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_998d3e67-d11e-460b-9655-52472b5c3098" xlink:to="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets_f3b65d55-6b0c-47e7-b3cb-139a901f5eec" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid_1236c8bc-5a68-4234-be20-4707512125a8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_998d3e67-d11e-460b-9655-52472b5c3098" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid_1236c8bc-5a68-4234-be20-4707512125a8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_bcad780e-1ff0-4895-9a8c-757e28d7bc54" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/EmployeeBenefitPlansFairValueofPlanAssetsDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#EmployeeBenefitPlansFairValueofPlanAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/EmployeeBenefitPlansFairValueofPlanAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_49990942-328d-49aa-923e-a5d4d7a1a9b0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_ad11a4c2-51a4-4fe6-b916-08a373ad1896" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_49990942-328d-49aa-923e-a5d4d7a1a9b0" xlink:to="loc_us-gaap_StatementTable_ad11a4c2-51a4-4fe6-b916-08a373ad1896" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_578b6c4c-da48-4691-b08d-bc4935ed0037" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_ad11a4c2-51a4-4fe6-b916-08a373ad1896" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_578b6c4c-da48-4691-b08d-bc4935ed0037" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_578b6c4c-da48-4691-b08d-bc4935ed0037_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_578b6c4c-da48-4691-b08d-bc4935ed0037" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_578b6c4c-da48-4691-b08d-bc4935ed0037_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_8eddbadc-da9e-4b30-9bdd-f2b455141bca" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_578b6c4c-da48-4691-b08d-bc4935ed0037" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_8eddbadc-da9e-4b30-9bdd-f2b455141bca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_c4454786-7ca4-4765-b278-3f57d9a696a1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_8eddbadc-da9e-4b30-9bdd-f2b455141bca" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_c4454786-7ca4-4765-b278-3f57d9a696a1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6ab52dfa-0b3e-45b1-b3ea-d9403f87fc24" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_ad11a4c2-51a4-4fe6-b916-08a373ad1896" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6ab52dfa-0b3e-45b1-b3ea-d9403f87fc24" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6ab52dfa-0b3e-45b1-b3ea-d9403f87fc24_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6ab52dfa-0b3e-45b1-b3ea-d9403f87fc24" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6ab52dfa-0b3e-45b1-b3ea-d9403f87fc24_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_47004d21-5d22-4a19-8f3c-ccdfef31a3de" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6ab52dfa-0b3e-45b1-b3ea-d9403f87fc24" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_47004d21-5d22-4a19-8f3c-ccdfef31a3de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_e3d5d841-8259-4a9c-82c2-c5bd8c7362b4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_47004d21-5d22-4a19-8f3c-ccdfef31a3de" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_e3d5d841-8259-4a9c-82c2-c5bd8c7362b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_e058f5a3-e981-433e-b5df-0dae44df3afd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_47004d21-5d22-4a19-8f3c-ccdfef31a3de" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_e058f5a3-e981-433e-b5df-0dae44df3afd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_0842d914-1d0c-4f40-9a3e-6451eb9046ad" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_47004d21-5d22-4a19-8f3c-ccdfef31a3de" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_0842d914-1d0c-4f40-9a3e-6451eb9046ad" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_396b3038-3e90-4f47-9f4b-d44a1dd0ecf5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_ad11a4c2-51a4-4fe6-b916-08a373ad1896" xlink:to="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_396b3038-3e90-4f47-9f4b-d44a1dd0ecf5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_396b3038-3e90-4f47-9f4b-d44a1dd0ecf5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_396b3038-3e90-4f47-9f4b-d44a1dd0ecf5" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_396b3038-3e90-4f47-9f4b-d44a1dd0ecf5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_d2d9d533-decd-4a02-b454-f81915eab4df" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_396b3038-3e90-4f47-9f4b-d44a1dd0ecf5" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_d2d9d533-decd-4a02-b454-f81915eab4df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanCashMember_336e0a65-efb7-4ccf-8e7a-6809f8d2e42a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanCashMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_d2d9d533-decd-4a02-b454-f81915eab4df" xlink:to="loc_us-gaap_DefinedBenefitPlanCashMember_336e0a65-efb7-4ccf-8e7a-6809f8d2e42a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDebtSecurityMember_4ff542c7-e785-4852-adee-4516e3b159f2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanDebtSecurityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_d2d9d533-decd-4a02-b454-f81915eab4df" xlink:to="loc_us-gaap_DefinedBenefitPlanDebtSecurityMember_4ff542c7-e785-4852-adee-4516e3b159f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember_3d2f9802-fa76-44ae-82f5-f4ec33de9511" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_d2d9d533-decd-4a02-b454-f81915eab4df" xlink:to="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember_3d2f9802-fa76-44ae-82f5-f4ec33de9511" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember_839c9880-0c16-46bd-8985-6e93ab6be587" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_d2d9d533-decd-4a02-b454-f81915eab4df" xlink:to="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember_839c9880-0c16-46bd-8985-6e93ab6be587" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations_cff0db8e-90e3-4794-9a35-1182a6b96fa8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_49990942-328d-49aa-923e-a5d4d7a1a9b0" xlink:to="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations_cff0db8e-90e3-4794-9a35-1182a6b96fa8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_3d620c55-8591-4da8-bb5d-73639518c8a0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_49990942-328d-49aa-923e-a5d4d7a1a9b0" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_3d620c55-8591-4da8-bb5d-73639518c8a0" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/EmployeeBenefitPlansComponentsofNetPensionExpenseDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#EmployeeBenefitPlansComponentsofNetPensionExpenseDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/EmployeeBenefitPlansComponentsofNetPensionExpenseDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_a6711bdd-0834-40e9-b2fc-4b00f6ffa756" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_bb905ecf-aeba-4b0b-9494-414fe0ced579" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_a6711bdd-0834-40e9-b2fc-4b00f6ffa756" xlink:to="loc_us-gaap_StatementTable_bb905ecf-aeba-4b0b-9494-414fe0ced579" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_301dffff-8d44-4f4e-93df-5b331cf9bfe4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_bb905ecf-aeba-4b0b-9494-414fe0ced579" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_301dffff-8d44-4f4e-93df-5b331cf9bfe4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_301dffff-8d44-4f4e-93df-5b331cf9bfe4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_301dffff-8d44-4f4e-93df-5b331cf9bfe4" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_301dffff-8d44-4f4e-93df-5b331cf9bfe4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_c6b42bc3-d882-49f2-aa65-d185ce8f7eb8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_301dffff-8d44-4f4e-93df-5b331cf9bfe4" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_c6b42bc3-d882-49f2-aa65-d185ce8f7eb8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_1dbb4354-711c-40f4-92f1-45246b32439c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_c6b42bc3-d882-49f2-aa65-d185ce8f7eb8" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_1dbb4354-711c-40f4-92f1-45246b32439c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_96a0358b-e474-4710-9dd1-60b611463e5f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_a6711bdd-0834-40e9-b2fc-4b00f6ffa756" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_96a0358b-e474-4710-9dd1-60b611463e5f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost_36a2d80f-7fce-4a6e-a647-ddc8b6891b88" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_96a0358b-e474-4710-9dd1-60b611463e5f" xlink:to="loc_us-gaap_DefinedBenefitPlanServiceCost_36a2d80f-7fce-4a6e-a647-ddc8b6891b88" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_29943be7-a649-4941-9f33-92ac402eae4a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_96a0358b-e474-4710-9dd1-60b611463e5f" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_29943be7-a649-4941-9f33-92ac402eae4a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_a8faa3c5-cf7b-449b-890d-d6f0014c1d4c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_96a0358b-e474-4710-9dd1-60b611463e5f" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_a8faa3c5-cf7b-449b-890d-d6f0014c1d4c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActuarialGainLossImmediateRecognitionAsComponentInNetPeriodicBenefitCostCredit_0da9e120-7ef5-4c25-9d71-4edd58549873" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanActuarialGainLossImmediateRecognitionAsComponentInNetPeriodicBenefitCostCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_96a0358b-e474-4710-9dd1-60b611463e5f" xlink:to="loc_us-gaap_DefinedBenefitPlanActuarialGainLossImmediateRecognitionAsComponentInNetPeriodicBenefitCostCredit_0da9e120-7ef5-4c25-9d71-4edd58549873" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_c1a11d62-8f05-4c8c-8862-419aaa828570" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_96a0358b-e474-4710-9dd1-60b611463e5f" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_c1a11d62-8f05-4c8c-8862-419aaa828570" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_d65c2ad4-f9d1-4687-9bbf-910f5ef42036" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_a6711bdd-0834-40e9-b2fc-4b00f6ffa756" xlink:to="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_d65c2ad4-f9d1-4687-9bbf-910f5ef42036" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_5876a2ed-7e19-44c0-bb8e-8a88d262a57f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_d65c2ad4-f9d1-4687-9bbf-910f5ef42036" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_5876a2ed-7e19-44c0-bb8e-8a88d262a57f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease_fec5ccad-f624-4619-8f80-f609ea6642f1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_d65c2ad4-f9d1-4687-9bbf-910f5ef42036" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease_fec5ccad-f624-4619-8f80-f609ea6642f1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationCashBalanceInterestCreditingRate_5264c3b7-a2a0-464e-8bc2-9dc1657afbf5" xlink:href="cme-20231231.xsd#cme_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationCashBalanceInterestCreditingRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_d65c2ad4-f9d1-4687-9bbf-910f5ef42036" xlink:to="loc_cme_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationCashBalanceInterestCreditingRate_5264c3b7-a2a0-464e-8bc2-9dc1657afbf5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_b7e067c3-bca7-45ff-8c02-58258359518b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_a6711bdd-0834-40e9-b2fc-4b00f6ffa756" xlink:to="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_b7e067c3-bca7-45ff-8c02-58258359518b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate_c0f6067a-bf9b-4eb1-95db-d08da8581e92" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_b7e067c3-bca7-45ff-8c02-58258359518b" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate_c0f6067a-bf9b-4eb1-95db-d08da8581e92" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease_926c837b-aba5-4fa4-a999-a86e853e2713" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_b7e067c3-bca7-45ff-8c02-58258359518b" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease_926c837b-aba5-4fa4-a999-a86e853e2713" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_a955e1da-10e3-4571-aedf-e72dce638dd5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_b7e067c3-bca7-45ff-8c02-58258359518b" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_a955e1da-10e3-4571-aedf-e72dce638dd5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostCashBalanceInterestCreditingRate_98b11591-74ee-4cef-920e-8c46f4230658" xlink:href="cme-20231231.xsd#cme_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostCashBalanceInterestCreditingRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_b7e067c3-bca7-45ff-8c02-58258359518b" xlink:to="loc_cme_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostCashBalanceInterestCreditingRate_98b11591-74ee-4cef-920e-8c46f4230658" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostWeightedAverageInterestCreditingRate_b4cf2254-1264-44fb-af97-23c9484f5f1b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostWeightedAverageInterestCreditingRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_a6711bdd-0834-40e9-b2fc-4b00f6ffa756" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostWeightedAverageInterestCreditingRate_b4cf2254-1264-44fb-af97-23c9484f5f1b" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/EmployeeBenefitPlansAssetAllocationforthePlanDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#EmployeeBenefitPlansAssetAllocationforthePlanDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/EmployeeBenefitPlansAssetAllocationforthePlanDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_d404b5a8-9296-470c-9141-feaba03dafdd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_2b9418b8-491b-4ecf-b398-62bea78d30aa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_d404b5a8-9296-470c-9141-feaba03dafdd" xlink:to="loc_us-gaap_StatementTable_2b9418b8-491b-4ecf-b398-62bea78d30aa" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_43ed765e-55cb-4746-9a49-c102f0362740" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_2b9418b8-491b-4ecf-b398-62bea78d30aa" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_43ed765e-55cb-4746-9a49-c102f0362740" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_43ed765e-55cb-4746-9a49-c102f0362740_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_43ed765e-55cb-4746-9a49-c102f0362740" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_43ed765e-55cb-4746-9a49-c102f0362740_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_ffefb01a-48ab-4bd7-bda3-9efda15e341b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_43ed765e-55cb-4746-9a49-c102f0362740" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_ffefb01a-48ab-4bd7-bda3-9efda15e341b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_1bc5b2e7-009b-46a3-a03a-f5cb1828e581" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_ffefb01a-48ab-4bd7-bda3-9efda15e341b" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_1bc5b2e7-009b-46a3-a03a-f5cb1828e581" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_c5d775c8-555e-4dbb-8083-6955d0b39ffa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_2b9418b8-491b-4ecf-b398-62bea78d30aa" xlink:to="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_c5d775c8-555e-4dbb-8083-6955d0b39ffa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_c5d775c8-555e-4dbb-8083-6955d0b39ffa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_c5d775c8-555e-4dbb-8083-6955d0b39ffa" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_c5d775c8-555e-4dbb-8083-6955d0b39ffa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_4eb870a9-5f99-4c00-a79a-ac8823389137" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_c5d775c8-555e-4dbb-8083-6955d0b39ffa" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_4eb870a9-5f99-4c00-a79a-ac8823389137" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations_1e389a8b-8292-4535-ab38-0be2e08722db" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d404b5a8-9296-470c-9141-feaba03dafdd" xlink:to="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations_1e389a8b-8292-4535-ab38-0be2e08722db" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/EmployeeBenefitPlansAccumulatedOtherComprehensiveIncomeLossofthePriorServiceCostsandActuarialLossesDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#EmployeeBenefitPlansAccumulatedOtherComprehensiveIncomeLossofthePriorServiceCostsandActuarialLossesDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/EmployeeBenefitPlansAccumulatedOtherComprehensiveIncomeLossofthePriorServiceCostsandActuarialLossesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_67c6063b-600e-49a9-aecb-88d50c8cb936" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_f29ea4ba-92b0-45bf-911f-94695f9e21af" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_67c6063b-600e-49a9-aecb-88d50c8cb936" xlink:to="loc_us-gaap_StatementTable_f29ea4ba-92b0-45bf-911f-94695f9e21af" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_bb204d1b-ef98-4729-bc4d-b2cf871b5afb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_f29ea4ba-92b0-45bf-911f-94695f9e21af" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_bb204d1b-ef98-4729-bc4d-b2cf871b5afb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_bb204d1b-ef98-4729-bc4d-b2cf871b5afb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_bb204d1b-ef98-4729-bc4d-b2cf871b5afb" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_bb204d1b-ef98-4729-bc4d-b2cf871b5afb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_f2c9dbd3-7941-4f5f-b536-d158103412ab" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_bb204d1b-ef98-4729-bc4d-b2cf871b5afb" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_f2c9dbd3-7941-4f5f-b536-d158103412ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_6fdd52eb-e3de-4a8d-ada6-9644a622af6e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_f2c9dbd3-7941-4f5f-b536-d158103412ab" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_6fdd52eb-e3de-4a8d-ada6-9644a622af6e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ActuarialLossesRollForward_4dfd67fe-b341-44d5-b5f9-a15c7945dcc3" xlink:href="cme-20231231.xsd#cme_ActuarialLossesRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_67c6063b-600e-49a9-aecb-88d50c8cb936" xlink:to="loc_cme_ActuarialLossesRollForward_4dfd67fe-b341-44d5-b5f9-a15c7945dcc3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax_74b38f00-e9f9-4560-8c5c-2f6ae213bf5a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cme_ActuarialLossesRollForward_4dfd67fe-b341-44d5-b5f9-a15c7945dcc3" xlink:to="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax_74b38f00-e9f9-4560-8c5c-2f6ae213bf5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax_904e1c3e-4642-46eb-9c72-25222c9a06cf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cme_ActuarialLossesRollForward_4dfd67fe-b341-44d5-b5f9-a15c7945dcc3" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax_904e1c3e-4642-46eb-9c72-25222c9a06cf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax_9055d460-9c82-4550-9dfa-4c5b88ad46c2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cme_ActuarialLossesRollForward_4dfd67fe-b341-44d5-b5f9-a15c7945dcc3" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax_9055d460-9c82-4550-9dfa-4c5b88ad46c2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax_4b63e789-a118-4fe5-bf14-802b6a6e420a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/EmployeeBenefitPlansAnticipatedBenefitPaymentsfromthePlaninFutureYearsDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#EmployeeBenefitPlansAnticipatedBenefitPaymentsfromthePlaninFutureYearsDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/EmployeeBenefitPlansAnticipatedBenefitPaymentsfromthePlaninFutureYearsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_22c40f8d-f8d5-4cf4-b916-85f2f1c19c8c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_4c05a823-910b-4a2a-8c31-e9f03cf8db84" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_22c40f8d-f8d5-4cf4-b916-85f2f1c19c8c" xlink:to="loc_us-gaap_StatementTable_4c05a823-910b-4a2a-8c31-e9f03cf8db84" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_787f584b-a004-4944-99a1-545ba19d8d51" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_4c05a823-910b-4a2a-8c31-e9f03cf8db84" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_787f584b-a004-4944-99a1-545ba19d8d51" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_787f584b-a004-4944-99a1-545ba19d8d51_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_787f584b-a004-4944-99a1-545ba19d8d51" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_787f584b-a004-4944-99a1-545ba19d8d51_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_3101228c-7d0e-4388-a1be-38a262866cda" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_787f584b-a004-4944-99a1-545ba19d8d51" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_3101228c-7d0e-4388-a1be-38a262866cda" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_26495fb2-d3bc-455e-8bfb-a8425428035d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_3101228c-7d0e-4388-a1be-38a262866cda" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_26495fb2-d3bc-455e-8bfb-a8425428035d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_5d389bd8-ca39-4459-8b9c-ccf3c325807c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_22c40f8d-f8d5-4cf4-b916-85f2f1c19c8c" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_5d389bd8-ca39-4459-8b9c-ccf3c325807c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_6314cf36-5a2f-4130-8086-e4ce12cc39a2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_22c40f8d-f8d5-4cf4-b916-85f2f1c19c8c" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_6314cf36-5a2f-4130-8086-e4ce12cc39a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_4d6b0149-1a7c-4278-802d-36fccd0869e7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_22c40f8d-f8d5-4cf4-b916-85f2f1c19c8c" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_4d6b0149-1a7c-4278-802d-36fccd0869e7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_184738ea-a8db-4d7e-9a78-0129a92271eb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_22c40f8d-f8d5-4cf4-b916-85f2f1c19c8c" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_184738ea-a8db-4d7e-9a78-0129a92271eb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_149a7497-2e9f-4671-bc96-1bf7bf10b7f3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_22c40f8d-f8d5-4cf4-b916-85f2f1c19c8c" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_149a7497-2e9f-4671-bc96-1bf7bf10b7f3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_994bbf37-d1a7-4024-8409-70ce9b5c9184" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_22c40f8d-f8d5-4cf4-b916-85f2f1c19c8c" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_994bbf37-d1a7-4024-8409-70ce9b5c9184" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/LeasesandOtherCommitmentsNarrativeDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#LeasesandOtherCommitmentsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/LeasesandOtherCommitmentsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_5d384e14-e1bb-4a97-a650-806c73085c76" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_9af60f31-c584-4557-a017-34e5f0ba21dc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_5d384e14-e1bb-4a97-a650-806c73085c76" xlink:to="loc_us-gaap_StatementTable_9af60f31-c584-4557-a017-34e5f0ba21dc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_4c1db024-2e93-4f8c-b8f2-3762e0c17c83" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9af60f31-c584-4557-a017-34e5f0ba21dc" xlink:to="loc_dei_LegalEntityAxis_4c1db024-2e93-4f8c-b8f2-3762e0c17c83" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_4c1db024-2e93-4f8c-b8f2-3762e0c17c83_default" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_4c1db024-2e93-4f8c-b8f2-3762e0c17c83" xlink:to="loc_dei_EntityDomain_4c1db024-2e93-4f8c-b8f2-3762e0c17c83_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_e1b16671-67a1-444e-9227-001a32661b7c" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_4c1db024-2e93-4f8c-b8f2-3762e0c17c83" xlink:to="loc_dei_EntityDomain_e1b16671-67a1-444e-9227-001a32661b7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseCost_cb3e5d01-7b76-492d-8401-a2c95b9b6eae" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5d384e14-e1bb-4a97-a650-806c73085c76" xlink:to="loc_us-gaap_OperatingLeaseCost_cb3e5d01-7b76-492d-8401-a2c95b9b6eae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_OperatingLeaseRenewalTerm_fae16f2f-ff84-43d0-a064-85e6ccac201e" xlink:href="cme-20231231.xsd#cme_OperatingLeaseRenewalTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5d384e14-e1bb-4a97-a650-806c73085c76" xlink:to="loc_cme_OperatingLeaseRenewalTerm_fae16f2f-ff84-43d0-a064-85e6ccac201e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_OperatingLeaseOptiontoEarlyTerminateMonths_449a8d1e-5f60-4a9d-a524-931532ef927e" xlink:href="cme-20231231.xsd#cme_OperatingLeaseOptiontoEarlyTerminateMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5d384e14-e1bb-4a97-a650-806c73085c76" xlink:to="loc_cme_OperatingLeaseOptiontoEarlyTerminateMonths_449a8d1e-5f60-4a9d-a524-931532ef927e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_OperatingLeaseTermofContract_3efeb899-0d05-4aab-b2aa-7a324339cf2e" xlink:href="cme-20231231.xsd#cme_OperatingLeaseTermofContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5d384e14-e1bb-4a97-a650-806c73085c76" xlink:to="loc_cme_OperatingLeaseTermofContract_3efeb899-0d05-4aab-b2aa-7a324339cf2e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_LeaseTermRecognitionBalanceSheet_b761533c-2a32-4c0e-b33e-73d53a3d4777" xlink:href="cme-20231231.xsd#cme_LeaseTermRecognitionBalanceSheet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5d384e14-e1bb-4a97-a650-806c73085c76" xlink:to="loc_cme_LeaseTermRecognitionBalanceSheet_b761533c-2a32-4c0e-b33e-73d53a3d4777" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermLeaseCost_83b11135-b9e1-4e16-8d2e-87f60a7fae2e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermLeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5d384e14-e1bb-4a97-a650-806c73085c76" xlink:to="loc_us-gaap_ShortTermLeaseCost_83b11135-b9e1-4e16-8d2e-87f60a7fae2e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseExpense_1c2af0f9-5147-4e88-b94d-2a9e634f1e41" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5d384e14-e1bb-4a97-a650-806c73085c76" xlink:to="loc_us-gaap_OperatingLeaseExpense_1c2af0f9-5147-4e88-b94d-2a9e634f1e41" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseInterestExpense_17ae6c67-ad8e-4c0d-ae80-20b2b2e1511f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseInterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5d384e14-e1bb-4a97-a650-806c73085c76" xlink:to="loc_us-gaap_FinanceLeaseInterestExpense_17ae6c67-ad8e-4c0d-ae80-20b2b2e1511f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetAmortization_91e8ca5b-1d05-4f87-9489-948416d534ef" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseRightOfUseAssetAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5d384e14-e1bb-4a97-a650-806c73085c76" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAssetAmortization_91e8ca5b-1d05-4f87-9489-948416d534ef" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_FinanceLeaseExpense_2bb4fd7d-574b-4dce-9c42-c8bdb042b525" xlink:href="cme-20231231.xsd#cme_FinanceLeaseExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5d384e14-e1bb-4a97-a650-806c73085c76" xlink:to="loc_cme_FinanceLeaseExpense_2bb4fd7d-574b-4dce-9c42-c8bdb042b525" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubleaseIncome_11e97f44-8703-49e8-acc1-e8e21e2d7408" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SubleaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5d384e14-e1bb-4a97-a650-806c73085c76" xlink:to="loc_us-gaap_SubleaseIncome_11e97f44-8703-49e8-acc1-e8e21e2d7408" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/LeasesandOtherCommitmentsSupplementalBalanceSheetInformationLeasesDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#LeasesandOtherCommitmentsSupplementalBalanceSheetInformationLeasesDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/LeasesandOtherCommitmentsSupplementalBalanceSheetInformationLeasesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_3a0fc72f-6c45-4863-8346-2d49f676a121" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_4544fb9e-6893-423d-ad5c-a4ae2b362566" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_3a0fc72f-6c45-4863-8346-2d49f676a121" xlink:to="loc_us-gaap_StatementTable_4544fb9e-6893-423d-ad5c-a4ae2b362566" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_0a4a83c0-0a08-4b96-8b07-7711b743fbc2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_4544fb9e-6893-423d-ad5c-a4ae2b362566" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_0a4a83c0-0a08-4b96-8b07-7711b743fbc2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_0a4a83c0-0a08-4b96-8b07-7711b743fbc2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_0a4a83c0-0a08-4b96-8b07-7711b743fbc2" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_0a4a83c0-0a08-4b96-8b07-7711b743fbc2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_8bd017c4-3544-4db1-b125-555ab51f12cf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_0a4a83c0-0a08-4b96-8b07-7711b743fbc2" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_8bd017c4-3544-4db1-b125-555ab51f12cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCurrentLiabilitiesMember_085023c4-fca3-473a-a21a-b1eec1d60df2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherCurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_8bd017c4-3544-4db1-b125-555ab51f12cf" xlink:to="loc_us-gaap_OtherCurrentLiabilitiesMember_085023c4-fca3-473a-a21a-b1eec1d60df2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentLiabilitiesMember_8fc44908-284d-48fe-a1a1-15aae1f0dcc5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherNoncurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_8bd017c4-3544-4db1-b125-555ab51f12cf" xlink:to="loc_us-gaap_OtherNoncurrentLiabilitiesMember_8fc44908-284d-48fe-a1a1-15aae1f0dcc5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityMember_07b6fb7f-92dd-497a-94a0-21ff71c36ba5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_8bd017c4-3544-4db1-b125-555ab51f12cf" xlink:to="loc_us-gaap_LiabilityMember_07b6fb7f-92dd-497a-94a0-21ff71c36ba5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_afae79a5-cde1-46ea-93af-cad1647120f7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3a0fc72f-6c45-4863-8346-2d49f676a121" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_afae79a5-cde1-46ea-93af-cad1647120f7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList_48d8ed3a-d5d3-4bf3-a579-630b4daf3651" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3a0fc72f-6c45-4863-8346-2d49f676a121" xlink:to="loc_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList_48d8ed3a-d5d3-4bf3-a579-630b4daf3651" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_84c762b6-c984-4508-932f-57a332223d3f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3a0fc72f-6c45-4863-8346-2d49f676a121" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_84c762b6-c984-4508-932f-57a332223d3f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_c8356150-7eff-4c52-8d11-2408a5e7eb0b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3a0fc72f-6c45-4863-8346-2d49f676a121" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_c8356150-7eff-4c52-8d11-2408a5e7eb0b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_6bed51ab-b4a0-4432-9b7e-e90e3ff9fe6c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3a0fc72f-6c45-4863-8346-2d49f676a121" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_6bed51ab-b4a0-4432-9b7e-e90e3ff9fe6c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList_fcb8f184-336b-4131-8dbf-12fda38a06e9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3a0fc72f-6c45-4863-8346-2d49f676a121" xlink:to="loc_us-gaap_FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList_fcb8f184-336b-4131-8dbf-12fda38a06e9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1_49b4a9b2-bb38-44a4-86e1-6c6194d5483f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3a0fc72f-6c45-4863-8346-2d49f676a121" xlink:to="loc_us-gaap_FinanceLeaseWeightedAverageRemainingLeaseTerm1_49b4a9b2-bb38-44a4-86e1-6c6194d5483f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent_186f700f-a0ca-4506-9b45-9885b08a369f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3a0fc72f-6c45-4863-8346-2d49f676a121" xlink:to="loc_us-gaap_FinanceLeaseWeightedAverageDiscountRatePercent_186f700f-a0ca-4506-9b45-9885b08a369f" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/LeasesandOtherCommitmentsOperatingLeasesFutureMinimumPaymentsDueDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#LeasesandOtherCommitmentsOperatingLeasesFutureMinimumPaymentsDueDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/LeasesandOtherCommitmentsOperatingLeasesFutureMinimumPaymentsDueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_70f6517e-e58b-4259-bf7b-16a93f95110a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_a2c2fe59-876a-4ff6-9221-38bbc81908e1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_70f6517e-e58b-4259-bf7b-16a93f95110a" xlink:to="loc_us-gaap_StatementTable_a2c2fe59-876a-4ff6-9221-38bbc81908e1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_f8987431-8d64-450b-a11f-7f0f2c7d6afb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_a2c2fe59-876a-4ff6-9221-38bbc81908e1" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_f8987431-8d64-450b-a11f-7f0f2c7d6afb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_f8987431-8d64-450b-a11f-7f0f2c7d6afb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_f8987431-8d64-450b-a11f-7f0f2c7d6afb" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_f8987431-8d64-450b-a11f-7f0f2c7d6afb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_b6045a04-360a-4cfb-b247-0f9a00d6bf1f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_f8987431-8d64-450b-a11f-7f0f2c7d6afb" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_b6045a04-360a-4cfb-b247-0f9a00d6bf1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityMember_a772c22d-571b-42c7-8370-c064805742bd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_b6045a04-360a-4cfb-b247-0f9a00d6bf1f" xlink:to="loc_us-gaap_LiabilityMember_a772c22d-571b-42c7-8370-c064805742bd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_a58cf25e-af88-4a16-8a49-7e45f7165a03" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70f6517e-e58b-4259-bf7b-16a93f95110a" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_a58cf25e-af88-4a16-8a49-7e45f7165a03" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_9d2ca7d2-3166-466d-a6f4-5999af318c5e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70f6517e-e58b-4259-bf7b-16a93f95110a" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_9d2ca7d2-3166-466d-a6f4-5999af318c5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_0bee73f6-8f6b-4854-acb2-efbcb8387cb3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70f6517e-e58b-4259-bf7b-16a93f95110a" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_0bee73f6-8f6b-4854-acb2-efbcb8387cb3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_c7f84755-2415-412c-961c-4304f1c5b605" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70f6517e-e58b-4259-bf7b-16a93f95110a" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_c7f84755-2415-412c-961c-4304f1c5b605" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_ca8078e9-dd29-4470-ba97-8e059751948e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70f6517e-e58b-4259-bf7b-16a93f95110a" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_ca8078e9-dd29-4470-ba97-8e059751948e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_1723cca9-de36-4877-934c-9c4f60087a5b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70f6517e-e58b-4259-bf7b-16a93f95110a" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_1723cca9-de36-4877-934c-9c4f60087a5b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_6dc059a0-3894-40b2-bb28-bbe7ca0d2106" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70f6517e-e58b-4259-bf7b-16a93f95110a" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_6dc059a0-3894-40b2-bb28-bbe7ca0d2106" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_ea37cc74-d13a-4c68-a320-1b55d65af890" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70f6517e-e58b-4259-bf7b-16a93f95110a" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_ea37cc74-d13a-4c68-a320-1b55d65af890" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList_fe0a357e-8748-43fb-bde7-9cf40ab92e8a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_70f6517e-e58b-4259-bf7b-16a93f95110a" xlink:to="loc_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList_fe0a357e-8748-43fb-bde7-9cf40ab92e8a" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/LeasesandOtherCommitmentsCapitalLeaseFutureMinimumPaymentsDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#LeasesandOtherCommitmentsCapitalLeaseFutureMinimumPaymentsDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/LeasesandOtherCommitmentsCapitalLeaseFutureMinimumPaymentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_16c94873-57e7-4e17-869f-877e473e1fe9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_31f1a9c8-65c2-4567-9932-223a9ec08930" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_16c94873-57e7-4e17-869f-877e473e1fe9" xlink:to="loc_us-gaap_StatementTable_31f1a9c8-65c2-4567-9932-223a9ec08930" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_220d3c0b-5954-4cad-b589-d5be052d795e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_31f1a9c8-65c2-4567-9932-223a9ec08930" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_220d3c0b-5954-4cad-b589-d5be052d795e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_220d3c0b-5954-4cad-b589-d5be052d795e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_220d3c0b-5954-4cad-b589-d5be052d795e" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_220d3c0b-5954-4cad-b589-d5be052d795e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_7ca87fcb-9cbd-4c13-a9b7-0291b3dda046" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_220d3c0b-5954-4cad-b589-d5be052d795e" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_7ca87fcb-9cbd-4c13-a9b7-0291b3dda046" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityMember_970e1e0d-55cb-4ca3-ab4b-49ab09a8daa9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_7ca87fcb-9cbd-4c13-a9b7-0291b3dda046" xlink:to="loc_us-gaap_LiabilityMember_970e1e0d-55cb-4ca3-ab4b-49ab09a8daa9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_468851d8-033f-4be9-9fee-3cdee14d39a7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_16c94873-57e7-4e17-869f-877e473e1fe9" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_468851d8-033f-4be9-9fee-3cdee14d39a7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo_b68700d1-b8ef-485c-b1c6-c821a17e475d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_16c94873-57e7-4e17-869f-877e473e1fe9" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo_b68700d1-b8ef-485c-b1c6-c821a17e475d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree_aa803f9f-9c73-4d0d-a30e-63dad199ab65" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_16c94873-57e7-4e17-869f-877e473e1fe9" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree_aa803f9f-9c73-4d0d-a30e-63dad199ab65" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour_f07df79d-cda6-4f62-bd9b-d63df3b02c3b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_16c94873-57e7-4e17-869f-877e473e1fe9" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFour_f07df79d-cda6-4f62-bd9b-d63df3b02c3b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive_7df2302a-933b-4bb7-8b0f-8f1699d25e7d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_16c94873-57e7-4e17-869f-877e473e1fe9" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive_7df2302a-933b-4bb7-8b0f-8f1699d25e7d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive_bca86645-a3bc-4a7f-a58f-034f31d18786" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_16c94873-57e7-4e17-869f-877e473e1fe9" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueAfterYearFive_bca86645-a3bc-4a7f-a58f-034f31d18786" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue_e1961b95-9b6c-4d50-bb25-23a463b9ead2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_16c94873-57e7-4e17-869f-877e473e1fe9" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue_e1961b95-9b6c-4d50-bb25-23a463b9ead2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_325fdc52-f2c8-4209-9779-66dd9cb3483b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_16c94873-57e7-4e17-869f-877e473e1fe9" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_325fdc52-f2c8-4209-9779-66dd9cb3483b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_057610b5-5c68-4767-8d19-f29ae028d5c4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_16c94873-57e7-4e17-869f-877e473e1fe9" xlink:to="loc_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_057610b5-5c68-4767-8d19-f29ae028d5c4" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList_0efc1281-2cea-4907-8fec-0c32cd1cc78c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_16c94873-57e7-4e17-869f-877e473e1fe9" xlink:to="loc_us-gaap_FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList_0efc1281-2cea-4907-8fec-0c32cd1cc78c" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/GuaranteesDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#GuaranteesDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/GuaranteesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsLineItems_df52ff79-eb87-445c-ba64-49c415ba183d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GuaranteeObligationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_780f9ab2-ac21-4d02-aaa5-0ef78194d0ed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfGuaranteeObligationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_df52ff79-eb87-445c-ba64-49c415ba183d" xlink:to="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_780f9ab2-ac21-4d02-aaa5-0ef78194d0ed" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsByNatureAxis_3ae41eb5-4218-4811-9a37-a169864714ed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GuaranteeObligationsByNatureAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_780f9ab2-ac21-4d02-aaa5-0ef78194d0ed" xlink:to="loc_us-gaap_GuaranteeObligationsByNatureAxis_3ae41eb5-4218-4811-9a37-a169864714ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_3ae41eb5-4218-4811-9a37-a169864714ed_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_3ae41eb5-4218-4811-9a37-a169864714ed" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_3ae41eb5-4218-4811-9a37-a169864714ed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_9bb92565-df2d-4349-80d7-c21dad9a88b7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_3ae41eb5-4218-4811-9a37-a169864714ed" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_9bb92565-df2d-4349-80d7-c21dad9a88b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_FamilyFarmerAndRanchersProtectionFundMember_7330e831-0eb6-40f8-a33f-7a9ee69d1aa2" xlink:href="cme-20231231.xsd#cme_FamilyFarmerAndRanchersProtectionFundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_9bb92565-df2d-4349-80d7-c21dad9a88b7" xlink:to="loc_cme_FamilyFarmerAndRanchersProtectionFundMember_7330e831-0eb6-40f8-a33f-7a9ee69d1aa2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnderlyingAssetClassAxis_20b3472b-aedf-48a6-b4ee-0f997b8165c6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnderlyingAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_780f9ab2-ac21-4d02-aaa5-0ef78194d0ed" xlink:to="loc_us-gaap_UnderlyingAssetClassAxis_20b3472b-aedf-48a6-b4ee-0f997b8165c6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnderlyingAssetClassDomain_20b3472b-aedf-48a6-b4ee-0f997b8165c6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnderlyingAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_UnderlyingAssetClassAxis_20b3472b-aedf-48a6-b4ee-0f997b8165c6" xlink:to="loc_us-gaap_UnderlyingAssetClassDomain_20b3472b-aedf-48a6-b4ee-0f997b8165c6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnderlyingAssetClassDomain_42a7d60e-7b9e-4df5-bef0-353dd61ef872" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnderlyingAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_UnderlyingAssetClassAxis_20b3472b-aedf-48a6-b4ee-0f997b8165c6" xlink:to="loc_us-gaap_UnderlyingAssetClassDomain_42a7d60e-7b9e-4df5-bef0-353dd61ef872" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_Paymentperparticipant_e1a9a5a2-ec32-4116-b6e5-a0460bf572c8" xlink:href="cme-20231231.xsd#cme_Paymentperparticipant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_df52ff79-eb87-445c-ba64-49c415ba183d" xlink:to="loc_cme_Paymentperparticipant_e1a9a5a2-ec32-4116-b6e5-a0460bf572c8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_GuaranteeCollateral_69eb65a7-4119-4811-bdbf-55b4e17e34b6" xlink:href="cme-20231231.xsd#cme_GuaranteeCollateral"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_df52ff79-eb87-445c-ba64-49c415ba183d" xlink:to="loc_cme_GuaranteeCollateral_69eb65a7-4119-4811-bdbf-55b4e17e34b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_Paymentpercooperative_1ac61e06-740b-43b5-8d37-d727ec39ea2a" xlink:href="cme-20231231.xsd#cme_Paymentpercooperative"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_df52ff79-eb87-445c-ba64-49c415ba183d" xlink:to="loc_cme_Paymentpercooperative_1ac61e06-740b-43b5-8d37-d727ec39ea2a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_PaymentsunderGuarantee_058cfda3-ba76-4f9f-8b61-0c0f1506c34d" xlink:href="cme-20231231.xsd#cme_PaymentsunderGuarantee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_df52ff79-eb87-445c-ba64-49c415ba183d" xlink:to="loc_cme_PaymentsunderGuarantee_058cfda3-ba76-4f9f-8b61-0c0f1506c34d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_5e11585d-edd1-4c69-98d0-726ec6eb19d0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_df52ff79-eb87-445c-ba64-49c415ba183d" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_5e11585d-edd1-4c69-98d0-726ec6eb19d0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeeAmount_95582702-f3a3-4360-b9ab-24289f44d75c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityCommitmentFeeAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_df52ff79-eb87-445c-ba64-49c415ba183d" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeeAmount_95582702-f3a3-4360-b9ab-24289f44d75c" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/CapitalStockNarrativeDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#CapitalStockNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/CapitalStockNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_b86a0adb-5818-42d3-8a43-4f877ea94681" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_f71aac1d-015f-4700-8017-474acbe027b6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_b86a0adb-5818-42d3-8a43-4f877ea94681" xlink:to="loc_us-gaap_StatementTable_f71aac1d-015f-4700-8017-474acbe027b6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_fc2bbc87-a1ec-4dd2-bd42-a97418d1b023" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_f71aac1d-015f-4700-8017-474acbe027b6" xlink:to="loc_us-gaap_PlanNameAxis_fc2bbc87-a1ec-4dd2-bd42-a97418d1b023" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_fc2bbc87-a1ec-4dd2-bd42-a97418d1b023_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_fc2bbc87-a1ec-4dd2-bd42-a97418d1b023" xlink:to="loc_us-gaap_PlanNameDomain_fc2bbc87-a1ec-4dd2-bd42-a97418d1b023_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_97971996-0b8e-4634-ad4d-434156ce7e95" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_fc2bbc87-a1ec-4dd2-bd42-a97418d1b023" xlink:to="loc_us-gaap_PlanNameDomain_97971996-0b8e-4634-ad4d-434156ce7e95" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_CmeGroupOmnibusStockPlanMember_70da6a4d-3eb0-4751-96b8-c00f10ebdda7" xlink:href="cme-20231231.xsd#cme_CmeGroupOmnibusStockPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_97971996-0b8e-4634-ad4d-434156ce7e95" xlink:to="loc_cme_CmeGroupOmnibusStockPlanMember_70da6a4d-3eb0-4751-96b8-c00f10ebdda7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_DirectorStockPlanClassSharesMember_fe54b791-7ce0-4414-b422-b8dd3aca836f" xlink:href="cme-20231231.xsd#cme_DirectorStockPlanClassSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_97971996-0b8e-4634-ad4d-434156ce7e95" xlink:to="loc_cme_DirectorStockPlanClassSharesMember_fe54b791-7ce0-4414-b422-b8dd3aca836f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_EmployeeStockPurchasePlanClassSharesMember_12b10547-5348-40e8-9580-421ddb6fa34a" xlink:href="cme-20231231.xsd#cme_EmployeeStockPurchasePlanClassSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_97971996-0b8e-4634-ad4d-434156ce7e95" xlink:to="loc_cme_EmployeeStockPurchasePlanClassSharesMember_12b10547-5348-40e8-9580-421ddb6fa34a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_886a64d5-4c12-440c-bfa6-865bdb2522d4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_f71aac1d-015f-4700-8017-474acbe027b6" xlink:to="loc_us-gaap_StatementClassOfStockAxis_886a64d5-4c12-440c-bfa6-865bdb2522d4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_886a64d5-4c12-440c-bfa6-865bdb2522d4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_886a64d5-4c12-440c-bfa6-865bdb2522d4" xlink:to="loc_us-gaap_ClassOfStockDomain_886a64d5-4c12-440c-bfa6-865bdb2522d4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_4f740de0-f1e1-4a52-b8a8-0f0c391098fd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_886a64d5-4c12-440c-bfa6-865bdb2522d4" xlink:to="loc_us-gaap_ClassOfStockDomain_4f740de0-f1e1-4a52-b8a8-0f0c391098fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_d7f16d57-7ee6-464d-925d-856ceb7590cb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_4f740de0-f1e1-4a52-b8a8-0f0c391098fd" xlink:to="loc_us-gaap_CommonClassAMember_d7f16d57-7ee6-464d-925d-856ceb7590cb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassBMember_78f4197a-b494-4806-b44e-6f669f577a38" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonClassBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_4f740de0-f1e1-4a52-b8a8-0f0c391098fd" xlink:to="loc_us-gaap_CommonClassBMember_78f4197a-b494-4806-b44e-6f669f577a38" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClassBCommonStockClassB1Member_eef26a11-5cc6-4551-abb3-b0ad55e50c3a" xlink:href="cme-20231231.xsd#cme_ClassBCommonStockClassB1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_4f740de0-f1e1-4a52-b8a8-0f0c391098fd" xlink:to="loc_cme_ClassBCommonStockClassB1Member_eef26a11-5cc6-4551-abb3-b0ad55e50c3a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClassBCommonStockClassB2Member_aa739754-e59b-4dfe-a464-a519c63afe1a" xlink:href="cme-20231231.xsd#cme_ClassBCommonStockClassB2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_4f740de0-f1e1-4a52-b8a8-0f0c391098fd" xlink:to="loc_cme_ClassBCommonStockClassB2Member_aa739754-e59b-4dfe-a464-a519c63afe1a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClassBCommonStockClassB3Member_4224c0d2-27ce-4bfe-9597-b4a66fb1b17b" xlink:href="cme-20231231.xsd#cme_ClassBCommonStockClassB3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_4f740de0-f1e1-4a52-b8a8-0f0c391098fd" xlink:to="loc_cme_ClassBCommonStockClassB3Member_4224c0d2-27ce-4bfe-9597-b4a66fb1b17b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClassBCommonStockClassB4Member_368b780e-4e00-47d5-8720-e44b963c7ebe" xlink:href="cme-20231231.xsd#cme_ClassBCommonStockClassB4Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_4f740de0-f1e1-4a52-b8a8-0f0c391098fd" xlink:to="loc_cme_ClassBCommonStockClassB4Member_368b780e-4e00-47d5-8720-e44b963c7ebe" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClassBCommonStockClassB1B2B3Member_668c6d41-0aa1-4845-b714-14be733f0253" xlink:href="cme-20231231.xsd#cme_ClassBCommonStockClassB1B2B3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_4f740de0-f1e1-4a52-b8a8-0f0c391098fd" xlink:to="loc_cme_ClassBCommonStockClassB1B2B3Member_668c6d41-0aa1-4845-b714-14be733f0253" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertiblePreferredStockMember_4b2d82e5-f903-4956-933c-2719c68f9b5a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_4f740de0-f1e1-4a52-b8a8-0f0c391098fd" xlink:to="loc_us-gaap_ConvertiblePreferredStockMember_4b2d82e5-f903-4956-933c-2719c68f9b5a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_83358f73-d286-430a-8ccb-e287937f8893" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b86a0adb-5818-42d3-8a43-4f877ea94681" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_83358f73-d286-430a-8ccb-e287937f8893" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_NumberOfDirectors_9f547288-6e56-4115-8a0a-7a182b4b1036" xlink:href="cme-20231231.xsd#cme_NumberOfDirectors"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b86a0adb-5818-42d3-8a43-4f877ea94681" xlink:to="loc_cme_NumberOfDirectors_9f547288-6e56-4115-8a0a-7a182b4b1036" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_d61a966a-63ea-4af3-98d6-e622ff406760" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b86a0adb-5818-42d3-8a43-4f877ea94681" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_d61a966a-63ea-4af3-98d6-e622ff406760" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_MarketValueOfSharesEmployeeStockPurchasePlan_498c3934-1991-46ea-82c1-0d85b3ac1444" xlink:href="cme-20231231.xsd#cme_MarketValueOfSharesEmployeeStockPurchasePlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b86a0adb-5818-42d3-8a43-4f877ea94681" xlink:to="loc_cme_MarketValueOfSharesEmployeeStockPurchasePlan_498c3934-1991-46ea-82c1-0d85b3ac1444" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOwnershipPlanESOPSharesInESOP_23b964b5-aaff-4249-8234-182a1d704892" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeStockOwnershipPlanESOPSharesInESOP"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b86a0adb-5818-42d3-8a43-4f877ea94681" xlink:to="loc_us-gaap_EmployeeStockOwnershipPlanESOPSharesInESOP_23b964b5-aaff-4249-8234-182a1d704892" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesIssued_ac78a587-d7f9-48bb-a667-1b0e4c1e2e05" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b86a0adb-5818-42d3-8a43-4f877ea94681" xlink:to="loc_us-gaap_PreferredStockSharesIssued_ac78a587-d7f9-48bb-a667-1b0e4c1e2e05" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/CapitalStockCapitalstockDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#CapitalStockCapitalstockDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/CapitalStockCapitalstockDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_79935600-a829-4b66-b6d5-ed570261e960" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_6d78c9e4-03f0-4257-855a-bca810cecd0e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_79935600-a829-4b66-b6d5-ed570261e960" xlink:to="loc_us-gaap_StatementTable_6d78c9e4-03f0-4257-855a-bca810cecd0e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_88283eb1-88ea-42d8-ae3a-276fd83fa476" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_6d78c9e4-03f0-4257-855a-bca810cecd0e" xlink:to="loc_us-gaap_PlanNameAxis_88283eb1-88ea-42d8-ae3a-276fd83fa476" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_88283eb1-88ea-42d8-ae3a-276fd83fa476_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_88283eb1-88ea-42d8-ae3a-276fd83fa476" xlink:to="loc_us-gaap_PlanNameDomain_88283eb1-88ea-42d8-ae3a-276fd83fa476_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_74dcdd05-b95d-4e8e-98de-34f2036fa24d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_88283eb1-88ea-42d8-ae3a-276fd83fa476" xlink:to="loc_us-gaap_PlanNameDomain_74dcdd05-b95d-4e8e-98de-34f2036fa24d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_CmeGroupOmnibusStockPlanMember_6612426b-715c-4d90-9b66-ea3f46229730" xlink:href="cme-20231231.xsd#cme_CmeGroupOmnibusStockPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_74dcdd05-b95d-4e8e-98de-34f2036fa24d" xlink:to="loc_cme_CmeGroupOmnibusStockPlanMember_6612426b-715c-4d90-9b66-ea3f46229730" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_DirectorStockPlanClassSharesMember_2dff7a45-3f38-40ce-85c0-efefe446495e" xlink:href="cme-20231231.xsd#cme_DirectorStockPlanClassSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_74dcdd05-b95d-4e8e-98de-34f2036fa24d" xlink:to="loc_cme_DirectorStockPlanClassSharesMember_2dff7a45-3f38-40ce-85c0-efefe446495e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_90fc01e8-94a0-42b5-8dbe-5e8cbcc404de" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_6d78c9e4-03f0-4257-855a-bca810cecd0e" xlink:to="loc_us-gaap_StatementClassOfStockAxis_90fc01e8-94a0-42b5-8dbe-5e8cbcc404de" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_90fc01e8-94a0-42b5-8dbe-5e8cbcc404de_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_90fc01e8-94a0-42b5-8dbe-5e8cbcc404de" xlink:to="loc_us-gaap_ClassOfStockDomain_90fc01e8-94a0-42b5-8dbe-5e8cbcc404de_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_f97ba93f-c54d-4a34-8555-c4f90f8ae07a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_90fc01e8-94a0-42b5-8dbe-5e8cbcc404de" xlink:to="loc_us-gaap_ClassOfStockDomain_f97ba93f-c54d-4a34-8555-c4f90f8ae07a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_cbbb814a-58b7-4dbe-a3fd-0aba86b6bb3b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_f97ba93f-c54d-4a34-8555-c4f90f8ae07a" xlink:to="loc_us-gaap_CommonClassAMember_cbbb814a-58b7-4dbe-a3fd-0aba86b6bb3b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClassBCommonStockClassB1Member_a8cd5ad5-81fd-47e2-b081-11431c3e0013" xlink:href="cme-20231231.xsd#cme_ClassBCommonStockClassB1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_f97ba93f-c54d-4a34-8555-c4f90f8ae07a" xlink:to="loc_cme_ClassBCommonStockClassB1Member_a8cd5ad5-81fd-47e2-b081-11431c3e0013" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClassBCommonStockClassB2Member_2e4a90b5-db15-4658-80e5-4c3753272155" xlink:href="cme-20231231.xsd#cme_ClassBCommonStockClassB2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_f97ba93f-c54d-4a34-8555-c4f90f8ae07a" xlink:to="loc_cme_ClassBCommonStockClassB2Member_2e4a90b5-db15-4658-80e5-4c3753272155" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClassBCommonStockClassB3Member_894f5624-8c92-4989-912d-d50877bfa7ab" xlink:href="cme-20231231.xsd#cme_ClassBCommonStockClassB3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_f97ba93f-c54d-4a34-8555-c4f90f8ae07a" xlink:to="loc_cme_ClassBCommonStockClassB3Member_894f5624-8c92-4989-912d-d50877bfa7ab" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClassBCommonStockClassB4Member_3e0e0a3e-1f2a-494a-b79a-3064c5c1b281" xlink:href="cme-20231231.xsd#cme_ClassBCommonStockClassB4Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_f97ba93f-c54d-4a34-8555-c4f90f8ae07a" xlink:to="loc_cme_ClassBCommonStockClassB4Member_3e0e0a3e-1f2a-494a-b79a-3064c5c1b281" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertiblePreferredStockMember_4bf40f12-c841-4232-94a7-46618cdbbdd7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConvertiblePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_f97ba93f-c54d-4a34-8555-c4f90f8ae07a" xlink:to="loc_us-gaap_ConvertiblePreferredStockMember_4bf40f12-c841-4232-94a7-46618cdbbdd7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_cc39ebbe-a50a-4cc5-8491-c1cbde3680ea" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_79935600-a829-4b66-b6d5-ed570261e960" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_cc39ebbe-a50a-4cc5-8491-c1cbde3680ea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_2b1c5450-3808-4b44-8072-e46964dae0f8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_79935600-a829-4b66-b6d5-ed570261e960" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_2b1c5450-3808-4b44-8072-e46964dae0f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_5915ad86-1e2f-4016-826e-f583fce0d125" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_79935600-a829-4b66-b6d5-ed570261e960" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_5915ad86-1e2f-4016-826e-f583fce0d125" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_0abfa473-c74b-45d8-8455-ac70f66a8f73" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_79935600-a829-4b66-b6d5-ed570261e960" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_0abfa473-c74b-45d8-8455-ac70f66a8f73" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_bbe46bd7-bddb-4b05-9606-f8f398f01cc3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_79935600-a829-4b66-b6d5-ed570261e960" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_bbe46bd7-bddb-4b05-9606-f8f398f01cc3" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/StockBasedPaymentsNarrativeDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#StockBasedPaymentsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/StockBasedPaymentsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_5662e44d-8dfb-4827-a561-7842b34d40d5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_us-gaap_StatementTable_5662e44d-8dfb-4827-a561-7842b34d40d5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_a9701e8f-d88f-4218-affe-24c822b05b6e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_5662e44d-8dfb-4827-a561-7842b34d40d5" xlink:to="loc_us-gaap_PlanNameAxis_a9701e8f-d88f-4218-affe-24c822b05b6e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_a9701e8f-d88f-4218-affe-24c822b05b6e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_a9701e8f-d88f-4218-affe-24c822b05b6e" xlink:to="loc_us-gaap_PlanNameDomain_a9701e8f-d88f-4218-affe-24c822b05b6e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_010c08b3-3c1c-494a-8828-a70eab8a4a0a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_a9701e8f-d88f-4218-affe-24c822b05b6e" xlink:to="loc_us-gaap_PlanNameDomain_010c08b3-3c1c-494a-8828-a70eab8a4a0a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_CmeGroupOmnibusStockPlanMember_c18b2596-2d46-414f-8173-2d1512dac69c" xlink:href="cme-20231231.xsd#cme_CmeGroupOmnibusStockPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_010c08b3-3c1c-494a-8828-a70eab8a4a0a" xlink:to="loc_cme_CmeGroupOmnibusStockPlanMember_c18b2596-2d46-414f-8173-2d1512dac69c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_20b13190-1fa4-45d3-9063-5bd3e3ea8eed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_5662e44d-8dfb-4827-a561-7842b34d40d5" xlink:to="loc_us-gaap_AwardTypeAxis_20b13190-1fa4-45d3-9063-5bd3e3ea8eed" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_20b13190-1fa4-45d3-9063-5bd3e3ea8eed_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_20b13190-1fa4-45d3-9063-5bd3e3ea8eed" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_20b13190-1fa4-45d3-9063-5bd3e3ea8eed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_085cb62e-8d0a-4fe1-bf49-3ab9ebb08079" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_20b13190-1fa4-45d3-9063-5bd3e3ea8eed" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_085cb62e-8d0a-4fe1-bf49-3ab9ebb08079" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_a9ff2801-8948-43be-99d0-bcedf1efdf33" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonClassAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_085cb62e-8d0a-4fe1-bf49-3ab9ebb08079" xlink:to="loc_us-gaap_CommonClassAMember_a9ff2801-8948-43be-99d0-bcedf1efdf33" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_a426c552-a000-4450-ad7d-c7023c4b4abc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_085cb62e-8d0a-4fe1-bf49-3ab9ebb08079" xlink:to="loc_us-gaap_PerformanceSharesMember_a426c552-a000-4450-ad7d-c7023c4b4abc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_b9500949-91a9-492a-b15c-c9abf986fc79" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_085cb62e-8d0a-4fe1-bf49-3ab9ebb08079" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_b9500949-91a9-492a-b15c-c9abf986fc79" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_8a50dde8-7ae2-4d2e-a3f3-604db0ee1f4a" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_5662e44d-8dfb-4827-a561-7842b34d40d5" xlink:to="loc_srt_RangeAxis_8a50dde8-7ae2-4d2e-a3f3-604db0ee1f4a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_8a50dde8-7ae2-4d2e-a3f3-604db0ee1f4a_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_8a50dde8-7ae2-4d2e-a3f3-604db0ee1f4a" xlink:to="loc_srt_RangeMember_8a50dde8-7ae2-4d2e-a3f3-604db0ee1f4a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_06c41dec-0753-420a-bb97-dce21e50948c" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_8a50dde8-7ae2-4d2e-a3f3-604db0ee1f4a" xlink:to="loc_srt_RangeMember_06c41dec-0753-420a-bb97-dce21e50948c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_1bd220bc-5f2a-4454-b05f-8c7364f2114b" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_06c41dec-0753-420a-bb97-dce21e50948c" xlink:to="loc_srt_MinimumMember_1bd220bc-5f2a-4454-b05f-8c7364f2114b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_ed5d522f-df7b-4b2f-a335-ccee883128f0" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_06c41dec-0753-420a-bb97-dce21e50948c" xlink:to="loc_srt_MaximumMember_ed5d522f-df7b-4b2f-a335-ccee883128f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_1790aab0-bc2d-4f8b-bc76-6257eb342898" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_5662e44d-8dfb-4827-a561-7842b34d40d5" xlink:to="loc_dei_LegalEntityAxis_1790aab0-bc2d-4f8b-bc76-6257eb342898" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_1790aab0-bc2d-4f8b-bc76-6257eb342898_default" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_1790aab0-bc2d-4f8b-bc76-6257eb342898" xlink:to="loc_dei_EntityDomain_1790aab0-bc2d-4f8b-bc76-6257eb342898_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_ea7bf3c7-228a-4fb0-ac1a-7cf608343754" xlink:href="https://xbrl.sec.gov/dei/2023/dei-2023.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_1790aab0-bc2d-4f8b-bc76-6257eb342898" xlink:to="loc_dei_EntityDomain_ea7bf3c7-228a-4fb0-ac1a-7cf608343754" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_DirectorStockPlanClassSharesMember_b47090f3-089a-49ef-8dd1-9d5a7bde2249" xlink:href="cme-20231231.xsd#cme_DirectorStockPlanClassSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_ea7bf3c7-228a-4fb0-ac1a-7cf608343754" xlink:to="loc_cme_DirectorStockPlanClassSharesMember_b47090f3-089a-49ef-8dd1-9d5a7bde2249" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_EmployeeStockPurchasePlanClassSharesMember_43230a06-9fd5-4001-88c4-8cb3783604a1" xlink:href="cme-20231231.xsd#cme_EmployeeStockPurchasePlanClassSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_ea7bf3c7-228a-4fb0-ac1a-7cf608343754" xlink:to="loc_cme_EmployeeStockPurchasePlanClassSharesMember_43230a06-9fd5-4001-88c4-8cb3783604a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_e31869bb-8cd3-43a0-9b77-f3da9f5f2250" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_e31869bb-8cd3-43a0-9b77-f3da9f5f2250" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_44089db6-dd75-4afc-be2a-55de86226163" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_44089db6-dd75-4afc-be2a-55de86226163" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_VestingPercentageAfterOneYear_77e47d55-72dc-4dfe-a944-3c82ded91d28" xlink:href="cme-20231231.xsd#cme_VestingPercentageAfterOneYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_cme_VestingPercentageAfterOneYear_77e47d55-72dc-4dfe-a944-3c82ded91d28" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_7b85505b-8eb5-4207-8456-52523d87df54" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_7b85505b-8eb5-4207-8456-52523d87df54" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_eefdfa41-b329-4486-b0a5-a7457a1b826c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_eefdfa41-b329-4486-b0a5-a7457a1b826c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_562b43d7-7e77-465f-89f5-9a8a6f7fa1cc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_562b43d7-7e77-465f-89f5-9a8a6f7fa1cc" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_a6458020-576a-4e99-b47b-9c953f8235ac" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_a6458020-576a-4e99-b47b-9c953f8235ac" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_8642bc8d-e68d-483e-92ab-7b1425ab3b36" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_8642bc8d-e68d-483e-92ab-7b1425ab3b36" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_ec752c3b-b8a5-4e71-b79e-fb862317a980" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_ec752c3b-b8a5-4e71-b79e-fb862317a980" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_b0e5ee4a-c0ff-4eed-892a-e6688de860da" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_b0e5ee4a-c0ff-4eed-892a-e6688de860da" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate_7e1bc861-3ecc-4b34-b444-967bb5cedf3f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate_7e1bc861-3ecc-4b34-b444-967bb5cedf3f" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_ClassCommonStockIssuedToParticipatingEmployees_17c8630f-7f14-4bc7-9bd1-668b71706b53" xlink:href="cme-20231231.xsd#cme_ClassCommonStockIssuedToParticipatingEmployees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_cme_ClassCommonStockIssuedToParticipatingEmployees_17c8630f-7f14-4bc7-9bd1-668b71706b53" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_AnnualAwardOfClassCommonStockValue_89c8dffa-1436-473c-b1ed-ffa0fd2e76dd" xlink:href="cme-20231231.xsd#cme_AnnualAwardOfClassCommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_cme_AnnualAwardOfClassCommonStockValue_89c8dffa-1436-473c-b1ed-ffa0fd2e76dd" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_AnnualStipendAllowanceInCash_035a4d23-e853-4ed0-9a87-24bafec39e07" xlink:href="cme-20231231.xsd#cme_AnnualStipendAllowanceInCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_cme_AnnualStipendAllowanceInCash_035a4d23-e853-4ed0-9a87-24bafec39e07" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_AnnualStipendAllowanceInSharesOfStockInShares_dc12db0a-3533-4095-a808-fd018888639a" xlink:href="cme-20231231.xsd#cme_AnnualStipendAllowanceInSharesOfStockInShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ccd21079-4248-4475-b53a-89c32eff921a" xlink:to="loc_cme_AnnualStipendAllowanceInSharesOfStockInShares_dc12db0a-3533-4095-a808-fd018888639a" xlink:type="arc" order="14"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/StockBasedPaymentsCompensationExpenseAndIncomeTaxBenefitRecognizedDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#StockBasedPaymentsCompensationExpenseAndIncomeTaxBenefitRecognizedDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/StockBasedPaymentsCompensationExpenseAndIncomeTaxBenefitRecognizedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_af48c542-bbb8-4ad1-9111-59250fec2424" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0fa3db71-054c-46d5-a365-5c8d714ec127" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_af48c542-bbb8-4ad1-9111-59250fec2424" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0fa3db71-054c-46d5-a365-5c8d714ec127" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_03c17b27-0af4-4cfe-af57-f306b7271984" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0fa3db71-054c-46d5-a365-5c8d714ec127" xlink:to="loc_us-gaap_PlanNameAxis_03c17b27-0af4-4cfe-af57-f306b7271984" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_03c17b27-0af4-4cfe-af57-f306b7271984_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_03c17b27-0af4-4cfe-af57-f306b7271984" xlink:to="loc_us-gaap_PlanNameDomain_03c17b27-0af4-4cfe-af57-f306b7271984_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_2f7577e6-8703-4ab7-a601-c4ca133f9cb4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_03c17b27-0af4-4cfe-af57-f306b7271984" xlink:to="loc_us-gaap_PlanNameDomain_2f7577e6-8703-4ab7-a601-c4ca133f9cb4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardDateAxis_b6161ce6-1ee9-4dd0-8d10-d79fb2f5e6eb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0fa3db71-054c-46d5-a365-5c8d714ec127" xlink:to="loc_us-gaap_AwardDateAxis_b6161ce6-1ee9-4dd0-8d10-d79fb2f5e6eb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardDateDomain_b6161ce6-1ee9-4dd0-8d10-d79fb2f5e6eb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardDateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardDateAxis_b6161ce6-1ee9-4dd0-8d10-d79fb2f5e6eb" xlink:to="loc_us-gaap_AwardDateDomain_b6161ce6-1ee9-4dd0-8d10-d79fb2f5e6eb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardDateDomain_b0bb4c1d-859c-4983-9482-6b0f8e58217d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardDateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardDateAxis_b6161ce6-1ee9-4dd0-8d10-d79fb2f5e6eb" xlink:to="loc_us-gaap_AwardDateDomain_b0bb4c1d-859c-4983-9482-6b0f8e58217d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_b48d4b20-51e0-4645-8936-1717dceb7d22" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0fa3db71-054c-46d5-a365-5c8d714ec127" xlink:to="loc_us-gaap_AwardTypeAxis_b48d4b20-51e0-4645-8936-1717dceb7d22" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b48d4b20-51e0-4645-8936-1717dceb7d22_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_b48d4b20-51e0-4645-8936-1717dceb7d22" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b48d4b20-51e0-4645-8936-1717dceb7d22_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_867ca78e-00cb-43cf-8215-e57180b117a1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_b48d4b20-51e0-4645-8936-1717dceb7d22" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_867ca78e-00cb-43cf-8215-e57180b117a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_f96b1b09-4e56-4c28-bb97-a6faedd31e47" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0fa3db71-054c-46d5-a365-5c8d714ec127" xlink:to="loc_us-gaap_StatementClassOfStockAxis_f96b1b09-4e56-4c28-bb97-a6faedd31e47" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_f96b1b09-4e56-4c28-bb97-a6faedd31e47_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_f96b1b09-4e56-4c28-bb97-a6faedd31e47" xlink:to="loc_us-gaap_ClassOfStockDomain_f96b1b09-4e56-4c28-bb97-a6faedd31e47_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_e7fb2124-0c08-4aba-a66c-3268d0591951" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_f96b1b09-4e56-4c28-bb97-a6faedd31e47" xlink:to="loc_us-gaap_ClassOfStockDomain_e7fb2124-0c08-4aba-a66c-3268d0591951" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_bf3e5946-5198-4c0a-8c17-2af01f5f2b83" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0fa3db71-054c-46d5-a365-5c8d714ec127" xlink:to="loc_srt_RangeAxis_bf3e5946-5198-4c0a-8c17-2af01f5f2b83" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_bf3e5946-5198-4c0a-8c17-2af01f5f2b83_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_bf3e5946-5198-4c0a-8c17-2af01f5f2b83" xlink:to="loc_srt_RangeMember_bf3e5946-5198-4c0a-8c17-2af01f5f2b83_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_9e3f9e24-f226-40d3-9d6f-90a2402da245" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_bf3e5946-5198-4c0a-8c17-2af01f5f2b83" xlink:to="loc_srt_RangeMember_9e3f9e24-f226-40d3-9d6f-90a2402da245" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingAxis_970e9e31-9566-499e-8066-3950dca80c4d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VestingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0fa3db71-054c-46d5-a365-5c8d714ec127" xlink:to="loc_us-gaap_VestingAxis_970e9e31-9566-499e-8066-3950dca80c4d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingDomain_970e9e31-9566-499e-8066-3950dca80c4d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VestingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VestingAxis_970e9e31-9566-499e-8066-3950dca80c4d" xlink:to="loc_us-gaap_VestingDomain_970e9e31-9566-499e-8066-3950dca80c4d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingDomain_f13c2620-dc02-40b5-8ab2-320d9969e00e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VestingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VestingAxis_970e9e31-9566-499e-8066-3950dca80c4d" xlink:to="loc_us-gaap_VestingDomain_f13c2620-dc02-40b5-8ab2-320d9969e00e" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/AccumulatedOtherComprehensiveIncomeLossScheduleofAccumulatedOtherComprehensiveIncomeDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#AccumulatedOtherComprehensiveIncomeLossScheduleofAccumulatedOtherComprehensiveIncomeDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/AccumulatedOtherComprehensiveIncomeLossScheduleofAccumulatedOtherComprehensiveIncomeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_17e2d47f-4564-46b3-9aab-2da1773c60ed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_4167eaa1-71cb-4b54-ab53-1f601a8ca121" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_17e2d47f-4564-46b3-9aab-2da1773c60ed" xlink:to="loc_us-gaap_StatementTable_4167eaa1-71cb-4b54-ab53-1f601a8ca121" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLocationAxis_562ea27e-5ce6-4105-9d8f-2e4b13fc94ad" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_4167eaa1-71cb-4b54-ab53-1f601a8ca121" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLocationAxis_562ea27e-5ce6-4105-9d8f-2e4b13fc94ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLocationDomain_562ea27e-5ce6-4105-9d8f-2e4b13fc94ad_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLocationAxis_562ea27e-5ce6-4105-9d8f-2e4b13fc94ad" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLocationDomain_562ea27e-5ce6-4105-9d8f-2e4b13fc94ad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLocationDomain_8a32de84-5557-447b-a3a4-e40a4b633fac" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLocationAxis_562ea27e-5ce6-4105-9d8f-2e4b13fc94ad" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLocationDomain_8a32de84-5557-447b-a3a4-e40a4b633fac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_b3461edf-8a04-447f-8db8-ad408043d097" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLocationDomain_8a32de84-5557-447b-a3a4-e40a4b633fac" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_b3461edf-8a04-447f-8db8-ad408043d097" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_e58fd2ca-89aa-487f-8fa9-ea46637c7c93" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLocationDomain_8a32de84-5557-447b-a3a4-e40a4b633fac" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_e58fd2ca-89aa-487f-8fa9-ea46637c7c93" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_89b32b90-076d-4647-b6be-ba5088aee759" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLocationDomain_8a32de84-5557-447b-a3a4-e40a4b633fac" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_89b32b90-076d-4647-b6be-ba5088aee759" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_545a0311-eeaa-458b-9d27-711da7a19399" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLocationDomain_8a32de84-5557-447b-a3a4-e40a4b633fac" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_545a0311-eeaa-458b-9d27-711da7a19399" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_49f5723b-87ed-4c2d-9df0-156d7422c827" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLocationDomain_8a32de84-5557-447b-a3a4-e40a4b633fac" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_49f5723b-87ed-4c2d-9df0-156d7422c827" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_22070690-ba92-46c5-a899-742fdc248b4a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_4167eaa1-71cb-4b54-ab53-1f601a8ca121" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_22070690-ba92-46c5-a899-742fdc248b4a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_22070690-ba92-46c5-a899-742fdc248b4a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_22070690-ba92-46c5-a899-742fdc248b4a" xlink:to="loc_us-gaap_EquityComponentDomain_22070690-ba92-46c5-a899-742fdc248b4a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_69b45afe-d479-497a-b938-5e706aa64c0b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_22070690-ba92-46c5-a899-742fdc248b4a" xlink:to="loc_us-gaap_EquityComponentDomain_69b45afe-d479-497a-b938-5e706aa64c0b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_0417f689-755d-4d30-96da-4d4bdffdf73f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_69b45afe-d479-497a-b938-5e706aa64c0b" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_0417f689-755d-4d30-96da-4d4bdffdf73f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_5c55ebae-eff8-408e-b948-117f4f1a941f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_69b45afe-d479-497a-b938-5e706aa64c0b" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_5c55ebae-eff8-408e-b948-117f4f1a941f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_17666a30-b81c-48c2-8918-58286558715b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_69b45afe-d479-497a-b938-5e706aa64c0b" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_17666a30-b81c-48c2-8918-58286558715b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_a35ae368-cabd-4f1c-99ac-ad691cf47734" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_69b45afe-d479-497a-b938-5e706aa64c0b" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_a35ae368-cabd-4f1c-99ac-ad691cf47734" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_AccumulatedOtherComprehensiveIncomeRollForward_d20e1ddc-a6cc-4765-ab01-56e5cdcc0431" xlink:href="cme-20231231.xsd#cme_AccumulatedOtherComprehensiveIncomeRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_17e2d47f-4564-46b3-9aab-2da1773c60ed" xlink:to="loc_cme_AccumulatedOtherComprehensiveIncomeRollForward_d20e1ddc-a6cc-4765-ab01-56e5cdcc0431" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_57b15cbd-24ec-432c-afa1-f4df0cd6e545" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cme_AccumulatedOtherComprehensiveIncomeRollForward_d20e1ddc-a6cc-4765-ab01-56e5cdcc0431" xlink:to="loc_us-gaap_StockholdersEquity_57b15cbd-24ec-432c-afa1-f4df0cd6e545" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_d2fd9dab-4584-4a03-9be2-63f0c3c86fba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cme_AccumulatedOtherComprehensiveIncomeRollForward_d20e1ddc-a6cc-4765-ab01-56e5cdcc0431" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_d2fd9dab-4584-4a03-9be2-63f0c3c86fba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax_ab8b6402-b13f-4c41-a848-0c161016335b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cme_AccumulatedOtherComprehensiveIncomeRollForward_d20e1ddc-a6cc-4765-ab01-56e5cdcc0431" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax_ab8b6402-b13f-4c41-a848-0c161016335b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTax_c487bcec-7dce-4a41-a296-e0f7cbf4e5b4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cme_AccumulatedOtherComprehensiveIncomeRollForward_d20e1ddc-a6cc-4765-ab01-56e5cdcc0431" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTax_c487bcec-7dce-4a41-a296-e0f7cbf4e5b4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_2d637aff-255e-4e99-9539-020e167d5eba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cme_AccumulatedOtherComprehensiveIncomeRollForward_d20e1ddc-a6cc-4765-ab01-56e5cdcc0431" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_2d637aff-255e-4e99-9539-020e167d5eba" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_1abc7530-2a77-4f25-89ea-4b21cf498f63" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/FairValueMeasurementsFinancialInstrumentsMeasuredatFairValueonaRecurringBasisDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#FairValueMeasurementsFinancialInstrumentsMeasuredatFairValueonaRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/FairValueMeasurementsFinancialInstrumentsMeasuredatFairValueonaRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_11ff3e74-29bd-4594-a38c-b06bdd8c94b6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_cdd7323d-8b6a-4cd6-8ac4-de04648f4c58" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_11ff3e74-29bd-4594-a38c-b06bdd8c94b6" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_cdd7323d-8b6a-4cd6-8ac4-de04648f4c58" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_ae1e0933-f605-4d9e-9c71-586851aeb0ed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_cdd7323d-8b6a-4cd6-8ac4-de04648f4c58" xlink:to="loc_us-gaap_FinancialInstrumentAxis_ae1e0933-f605-4d9e-9c71-586851aeb0ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ae1e0933-f605-4d9e-9c71-586851aeb0ed_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_ae1e0933-f605-4d9e-9c71-586851aeb0ed" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_ae1e0933-f605-4d9e-9c71-586851aeb0ed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_277e4092-6992-45c6-a806-e0a2685a573a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_ae1e0933-f605-4d9e-9c71-586851aeb0ed" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_277e4092-6992-45c6-a806-e0a2685a573a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_936f702d-f674-4392-b0e8-047b30b2c02e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_277e4092-6992-45c6-a806-e0a2685a573a" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_936f702d-f674-4392-b0e8-047b30b2c02e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MutualFundMember_728fba68-2553-49d3-b9db-180b3151360d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MutualFundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_277e4092-6992-45c6-a806-e0a2685a573a" xlink:to="loc_us-gaap_MutualFundMember_728fba68-2553-49d3-b9db-180b3151360d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesMember_5a342305-1588-417d-805c-4288b73c5e74" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquitySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_277e4092-6992-45c6-a806-e0a2685a573a" xlink:to="loc_us-gaap_EquitySecuritiesMember_5a342305-1588-417d-805c-4288b73c5e74" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_c140fcef-0c99-4650-a2fd-dbabff8ddb7e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_cdd7323d-8b6a-4cd6-8ac4-de04648f4c58" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_c140fcef-0c99-4650-a2fd-dbabff8ddb7e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_c140fcef-0c99-4650-a2fd-dbabff8ddb7e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_c140fcef-0c99-4650-a2fd-dbabff8ddb7e" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_c140fcef-0c99-4650-a2fd-dbabff8ddb7e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_077531cb-6ef6-41fe-973a-192b89c3468e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_c140fcef-0c99-4650-a2fd-dbabff8ddb7e" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_077531cb-6ef6-41fe-973a-192b89c3468e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_cd36263c-a1f6-46d8-accf-0982cf813533" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_077531cb-6ef6-41fe-973a-192b89c3468e" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_cd36263c-a1f6-46d8-accf-0982cf813533" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_91d5a165-112e-4584-a059-408915c91675" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_cdd7323d-8b6a-4cd6-8ac4-de04648f4c58" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_91d5a165-112e-4584-a059-408915c91675" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_91d5a165-112e-4584-a059-408915c91675_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_91d5a165-112e-4584-a059-408915c91675" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_91d5a165-112e-4584-a059-408915c91675_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_ba76439d-40c3-4103-8023-90e2d1922540" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_91d5a165-112e-4584-a059-408915c91675" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_ba76439d-40c3-4103-8023-90e2d1922540" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_ae2f1b83-b8a8-4239-b330-f08e93d0ee29" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_ba76439d-40c3-4103-8023-90e2d1922540" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_ae2f1b83-b8a8-4239-b330-f08e93d0ee29" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_0bf078d0-9e25-4762-9708-89c989c96de1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_ba76439d-40c3-4103-8023-90e2d1922540" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_0bf078d0-9e25-4762-9708-89c989c96de1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_9d63bef7-e8a2-48f4-8f6c-8c1584f5a0d4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_ba76439d-40c3-4103-8023-90e2d1922540" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_9d63bef7-e8a2-48f4-8f6c-8c1584f5a0d4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradingSecurities_79aa2204-d07e-46fd-9706-3f7c2309f9f1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TradingSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_11ff3e74-29bd-4594-a38c-b06bdd8c94b6" xlink:to="loc_us-gaap_TradingSecurities_79aa2204-d07e-46fd-9706-3f7c2309f9f1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsFairValueDisclosure_02f6885d-a4d2-428e-a1ab-56b254f9b118" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InvestmentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_11ff3e74-29bd-4594-a38c-b06bdd8c94b6" xlink:to="loc_us-gaap_InvestmentsFairValueDisclosure_02f6885d-a4d2-428e-a1ab-56b254f9b118" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarketableSecurities_2a3cfc6b-c8ab-4d42-939f-dbe4d3cb3ace" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MarketableSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_11ff3e74-29bd-4594-a38c-b06bdd8c94b6" xlink:to="loc_us-gaap_MarketableSecurities_2a3cfc6b-c8ab-4d42-939f-dbe4d3cb3ace" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_85b48b88-9324-455e-9955-7a0525b49de7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_11ff3e74-29bd-4594-a38c-b06bdd8c94b6" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_85b48b88-9324-455e-9955-7a0525b49de7" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/FairValueMeasurementsDebtInstrumentsDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#FairValueMeasurementsDebtInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/FairValueMeasurementsDebtInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_6fb09c66-3b0f-4d17-af9b-4641f2fc3ad0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_bf19b61b-63ec-42b0-80aa-0d9f368758a6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_6fb09c66-3b0f-4d17-af9b-4641f2fc3ad0" xlink:to="loc_us-gaap_StatementTable_bf19b61b-63ec-42b0-80aa-0d9f368758a6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_d528b900-bfc5-4da3-8d1a-3e47c9ce5bbf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_bf19b61b-63ec-42b0-80aa-0d9f368758a6" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_d528b900-bfc5-4da3-8d1a-3e47c9ce5bbf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d528b900-bfc5-4da3-8d1a-3e47c9ce5bbf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_d528b900-bfc5-4da3-8d1a-3e47c9ce5bbf" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d528b900-bfc5-4da3-8d1a-3e47c9ce5bbf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e64ea7c9-001e-4881-aca0-1884ae5532ca" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_d528b900-bfc5-4da3-8d1a-3e47c9ce5bbf" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e64ea7c9-001e-4881-aca0-1884ae5532ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_be33429b-852b-4a21-b4a1-bdd599017f75" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e64ea7c9-001e-4881-aca0-1884ae5532ca" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_be33429b-852b-4a21-b4a1-bdd599017f75" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_6045a991-8761-45e8-a1e9-e3df856112db" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e64ea7c9-001e-4881-aca0-1884ae5532ca" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_6045a991-8761-45e8-a1e9-e3df856112db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_1f049d0d-990e-4aa4-89dd-981ce4d2dc8f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_bf19b61b-63ec-42b0-80aa-0d9f368758a6" xlink:to="loc_us-gaap_DebtInstrumentAxis_1f049d0d-990e-4aa4-89dd-981ce4d2dc8f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_1f049d0d-990e-4aa4-89dd-981ce4d2dc8f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_1f049d0d-990e-4aa4-89dd-981ce4d2dc8f" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_1f049d0d-990e-4aa4-89dd-981ce4d2dc8f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_41005fd6-b103-450a-b32d-24784a97f097" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_1f049d0d-990e-4aa4-89dd-981ce4d2dc8f" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_41005fd6-b103-450a-b32d-24784a97f097" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_A750.0millionFixedRateNotesDueSeptember2022InterestEqualTo3.00Member_3f8cdc31-be41-449d-adc6-fae920f81547" xlink:href="cme-20231231.xsd#cme_A750.0millionFixedRateNotesDueSeptember2022InterestEqualTo3.00Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_41005fd6-b103-450a-b32d-24784a97f097" xlink:to="loc_cme_A750.0millionFixedRateNotesDueSeptember2022InterestEqualTo3.00Member_3f8cdc31-be41-449d-adc6-fae920f81547" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_A15.0millionfixedratenotesdueMay2023Member_5fff1565-f545-4904-9873-5e14f4938d1f" xlink:href="cme-20231231.xsd#cme_A15.0millionfixedratenotesdueMay2023Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_41005fd6-b103-450a-b32d-24784a97f097" xlink:to="loc_cme_A15.0millionfixedratenotesdueMay2023Member_5fff1565-f545-4904-9873-5e14f4938d1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_A750.0MillionFixedRateNotesDueMarch2025InterestEqualTo3.00Member_aae67189-03e3-4fa4-be62-122ac610b1ba" xlink:href="cme-20231231.xsd#cme_A750.0MillionFixedRateNotesDueMarch2025InterestEqualTo3.00Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_41005fd6-b103-450a-b32d-24784a97f097" xlink:to="loc_cme_A750.0MillionFixedRateNotesDueMarch2025InterestEqualTo3.00Member_aae67189-03e3-4fa4-be62-122ac610b1ba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_A500.0MillionFixedRateNotesDueJune2028InterestEqualTo3.75MemberDomain_f5e66347-4f56-4bda-a29a-dedb998bfa78" xlink:href="cme-20231231.xsd#cme_A500.0MillionFixedRateNotesDueJune2028InterestEqualTo3.75MemberDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_41005fd6-b103-450a-b32d-24784a97f097" xlink:to="loc_cme_A500.0MillionFixedRateNotesDueJune2028InterestEqualTo3.75MemberDomain_f5e66347-4f56-4bda-a29a-dedb998bfa78" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_A750.0millionFixedRateNotesDueSeptember2043InterestEqualTo5.3Member_e33651cc-9edb-46cc-befe-6f92d15e4e88" xlink:href="cme-20231231.xsd#cme_A750.0millionFixedRateNotesDueSeptember2043InterestEqualTo5.3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_41005fd6-b103-450a-b32d-24784a97f097" xlink:to="loc_cme_A750.0millionFixedRateNotesDueSeptember2043InterestEqualTo5.3Member_e33651cc-9edb-46cc-befe-6f92d15e4e88" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_A700.0MillionFixedRateNotesDueJune2048InterestEqualTo4.15MemberDomainDomain_d226dbea-ba74-460d-9f14-3f5cad5a1a2a" xlink:href="cme-20231231.xsd#cme_A700.0MillionFixedRateNotesDueJune2048InterestEqualTo4.15MemberDomainDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_41005fd6-b103-450a-b32d-24784a97f097" xlink:to="loc_cme_A700.0MillionFixedRateNotesDueJune2048InterestEqualTo4.15MemberDomainDomain_d226dbea-ba74-460d-9f14-3f5cad5a1a2a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_cme_A7500MillionFixedRateNotesDueMarch2032InterestEqualTo265Member_05b4353e-ae95-4eb5-92f8-436ccb27f4f7" xlink:href="cme-20231231.xsd#cme_A7500MillionFixedRateNotesDueMarch2032InterestEqualTo265Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_41005fd6-b103-450a-b32d-24784a97f097" xlink:to="loc_cme_A7500MillionFixedRateNotesDueMarch2032InterestEqualTo265Member_05b4353e-ae95-4eb5-92f8-436ccb27f4f7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFairValue_679ee991-8994-44c0-94d2-e3f3512a5466" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_6fb09c66-3b0f-4d17-af9b-4641f2fc3ad0" xlink:to="loc_us-gaap_DebtInstrumentFairValue_679ee991-8994-44c0-94d2-e3f3512a5466" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnsecuredLongTermDebt_a4eb59aa-87af-4a05-afd6-fc4460606c6c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnsecuredLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_6fb09c66-3b0f-4d17-af9b-4641f2fc3ad0" xlink:to="loc_us-gaap_UnsecuredLongTermDebt_a4eb59aa-87af-4a05-afd6-fc4460606c6c" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/FairValueMeasurementsNarrativeDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#FairValueMeasurementsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/FairValueMeasurementsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_247b3515-343c-46ef-a98a-9d574a2642ba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_dcccb10c-b412-4acb-921b-616030bfc047" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_247b3515-343c-46ef-a98a-9d574a2642ba" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_dcccb10c-b412-4acb-921b-616030bfc047" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_a775c1b4-ced0-4cc8-afd5-288189c80368" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_dcccb10c-b412-4acb-921b-616030bfc047" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_a775c1b4-ced0-4cc8-afd5-288189c80368" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_a775c1b4-ced0-4cc8-afd5-288189c80368_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_a775c1b4-ced0-4cc8-afd5-288189c80368" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_a775c1b4-ced0-4cc8-afd5-288189c80368_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_06b1efc3-9ae5-45de-b443-462ba3467bcc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_a775c1b4-ced0-4cc8-afd5-288189c80368" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_06b1efc3-9ae5-45de-b443-462ba3467bcc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrealizedGainLossOnInvestments_6cbf3c9a-7d3a-43e1-8502-683081c103f4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnrealizedGainLossOnInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_247b3515-343c-46ef-a98a-9d574a2642ba" xlink:to="loc_us-gaap_UnrealizedGainLossOnInvestments_6cbf3c9a-7d3a-43e1-8502-683081c103f4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsFairValueDisclosure_7f96c6d1-7a05-4300-86a3-906a9732d0d0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_InvestmentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_247b3515-343c-46ef-a98a-9d574a2642ba" xlink:to="loc_us-gaap_InvestmentsFairValueDisclosure_7f96c6d1-7a05-4300-86a3-906a9732d0d0" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/EarningsPerShareBasicandDilutedEarningsPerShareDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#EarningsPerShareBasicandDilutedEarningsPerShareDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/EarningsPerShareBasicandDilutedEarningsPerShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_5917cc9e-0de4-47ad-9dce-ae7cea98f1f1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_157d1ab5-57fa-408a-9c8c-62ff2c8003cb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_5917cc9e-0de4-47ad-9dce-ae7cea98f1f1" xlink:to="loc_us-gaap_StatementTable_157d1ab5-57fa-408a-9c8c-62ff2c8003cb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_4ca1d884-9a7b-41a8-8e14-5db849022c56" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_157d1ab5-57fa-408a-9c8c-62ff2c8003cb" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_4ca1d884-9a7b-41a8-8e14-5db849022c56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_4ca1d884-9a7b-41a8-8e14-5db849022c56_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_4ca1d884-9a7b-41a8-8e14-5db849022c56" xlink:to="loc_us-gaap_EquityComponentDomain_4ca1d884-9a7b-41a8-8e14-5db849022c56_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_d4826fbb-5f04-4bf8-822c-f3d1f586577e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_4ca1d884-9a7b-41a8-8e14-5db849022c56" xlink:to="loc_us-gaap_EquityComponentDomain_d4826fbb-5f04-4bf8-822c-f3d1f586577e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_de746d51-90fe-4dc4-b3a8-b96361590c28" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_d4826fbb-5f04-4bf8-822c-f3d1f586577e" xlink:to="loc_us-gaap_RetainedEarningsMember_de746d51-90fe-4dc4-b3a8-b96361590c28" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_6c51c693-b908-44d1-86dd-c0a9f12dc33d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_157d1ab5-57fa-408a-9c8c-62ff2c8003cb" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_6c51c693-b908-44d1-86dd-c0a9f12dc33d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_6c51c693-b908-44d1-86dd-c0a9f12dc33d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_6c51c693-b908-44d1-86dd-c0a9f12dc33d" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_6c51c693-b908-44d1-86dd-c0a9f12dc33d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_45213965-1607-4140-a7b2-7e19ea608a5a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_6c51c693-b908-44d1-86dd-c0a9f12dc33d" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_45213965-1607-4140-a7b2-7e19ea608a5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_f7f7d722-e957-4ca5-b333-0b5366441133" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_45213965-1607-4140-a7b2-7e19ea608a5a" xlink:to="loc_us-gaap_RestrictedStockMember_f7f7d722-e957-4ca5-b333-0b5366441133" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OptionIndexedToIssuersEquityTypeAxis_4af067ec-f6c7-4b1b-9bf5-53c115408098" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OptionIndexedToIssuersEquityTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_157d1ab5-57fa-408a-9c8c-62ff2c8003cb" xlink:to="loc_us-gaap_OptionIndexedToIssuersEquityTypeAxis_4af067ec-f6c7-4b1b-9bf5-53c115408098" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OptionIndexedToIssuersEquityTypeDomain_4af067ec-f6c7-4b1b-9bf5-53c115408098_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OptionIndexedToIssuersEquityTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OptionIndexedToIssuersEquityTypeAxis_4af067ec-f6c7-4b1b-9bf5-53c115408098" xlink:to="loc_us-gaap_OptionIndexedToIssuersEquityTypeDomain_4af067ec-f6c7-4b1b-9bf5-53c115408098_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OptionIndexedToIssuersEquityTypeDomain_e0266ff2-711e-411f-9cd0-2a60aa89587f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OptionIndexedToIssuersEquityTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OptionIndexedToIssuersEquityTypeAxis_4af067ec-f6c7-4b1b-9bf5-53c115408098" xlink:to="loc_us-gaap_OptionIndexedToIssuersEquityTypeDomain_e0266ff2-711e-411f-9cd0-2a60aa89587f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_ef3c2dfe-d6dd-4b4b-a86b-456f1fb81a83" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5917cc9e-0de4-47ad-9dce-ae7cea98f1f1" xlink:to="loc_us-gaap_NetIncomeLoss_ef3c2dfe-d6dd-4b4b-a86b-456f1fb81a83" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_59602c55-2c99-400f-908e-33bf8cf56357" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PreferredStockDividendsIncomeStatementImpact"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5917cc9e-0de4-47ad-9dce-ae7cea98f1f1" xlink:to="loc_us-gaap_PreferredStockDividendsIncomeStatementImpact_59602c55-2c99-400f-908e-33bf8cf56357" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic_8ceb4dd9-42c7-4ccb-a94e-60c7f0097a7b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5917cc9e-0de4-47ad-9dce-ae7cea98f1f1" xlink:to="loc_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic_8ceb4dd9-42c7-4ccb-a94e-60c7f0097a7b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_af9f3d07-cf86-4d17-9fef-3f6671723517" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5917cc9e-0de4-47ad-9dce-ae7cea98f1f1" xlink:to="loc_us-gaap_ProfitLoss_af9f3d07-cf86-4d17-9fef-3f6671723517" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_7ec4dc6c-a140-4012-adb9-39a2ea9dbb54" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5917cc9e-0de4-47ad-9dce-ae7cea98f1f1" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_7ec4dc6c-a140-4012-adb9-39a2ea9dbb54" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_61065f6e-b9b0-4309-8ec4-fd255790b7eb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5917cc9e-0de4-47ad-9dce-ae7cea98f1f1" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_61065f6e-b9b0-4309-8ec4-fd255790b7eb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_ee09c052-2faa-4897-82e4-82f25bfd7847" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5917cc9e-0de4-47ad-9dce-ae7cea98f1f1" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_ee09c052-2faa-4897-82e4-82f25bfd7847" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_6bb903b9-18cb-4c22-8ba3-06290b048044" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5917cc9e-0de4-47ad-9dce-ae7cea98f1f1" xlink:to="loc_us-gaap_EarningsPerShareBasic_6bb903b9-18cb-4c22-8ba3-06290b048044" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_0e273cbc-2f1a-4f55-a219-4f96a0a05706" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5917cc9e-0de4-47ad-9dce-ae7cea98f1f1" xlink:to="loc_us-gaap_EarningsPerShareDiluted_0e273cbc-2f1a-4f55-a219-4f96a0a05706" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_a7ebec7b-de30-4fea-a6da-b387df249bff" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5917cc9e-0de4-47ad-9dce-ae7cea98f1f1" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_a7ebec7b-de30-4fea-a6da-b387df249bff" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_ba2dfef6-7750-4e8c-bd55-60c51c570888" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5917cc9e-0de4-47ad-9dce-ae7cea98f1f1" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_ba2dfef6-7750-4e8c-bd55-60c51c570888" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.cmegroup.com/role/ScheduleIIValuationandQualifyingAccountsScheduleIIValuationandQualifyingAccountsDetails" xlink:type="simple" xlink:href="cme-20231231.xsd#ScheduleIIValuationandQualifyingAccountsScheduleIIValuationandQualifyingAccountsDetails"/>
  <link:definitionLink xlink:role="http://www.cmegroup.com/role/ScheduleIIValuationandQualifyingAccountsScheduleIIValuationandQualifyingAccountsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_c4cf7f57-6b31-4967-8dda-cb87b1d7e8b2" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ValuationAndQualifyingAccountsDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_a5b2a0d8-c7cf-4982-80b0-ccea68544278" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ValuationAndQualifyingAccountsDisclosureTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_c4cf7f57-6b31-4967-8dda-cb87b1d7e8b2" xlink:to="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_a5b2a0d8-c7cf-4982-80b0-ccea68544278" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_1e2efc4f-0842-4fb2-a091-9f609067fd89" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_a5b2a0d8-c7cf-4982-80b0-ccea68544278" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_1e2efc4f-0842-4fb2-a091-9f609067fd89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_1e2efc4f-0842-4fb2-a091-9f609067fd89_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_1e2efc4f-0842-4fb2-a091-9f609067fd89" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_1e2efc4f-0842-4fb2-a091-9f609067fd89_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_0f06ee55-38de-4276-b023-8a4ccf0c977e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_1e2efc4f-0842-4fb2-a091-9f609067fd89" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_0f06ee55-38de-4276-b023-8a4ccf0c977e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForCreditLossMember_b5b2a1da-862b-4d2e-b6e1-29f89c7e5b48" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AllowanceForCreditLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_0f06ee55-38de-4276-b023-8a4ccf0c977e" xlink:to="loc_us-gaap_AllowanceForCreditLossMember_b5b2a1da-862b-4d2e-b6e1-29f89c7e5b48" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember_07ac12bd-7f57-4a2e-be38-084564eb3081" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_0f06ee55-38de-4276-b023-8a4ccf0c977e" xlink:to="loc_us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember_07ac12bd-7f57-4a2e-be38-084564eb3081" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_63b084a9-7464-4a28-a188-1920ff95f232" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MovementInValuationAllowancesAndReservesRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_c4cf7f57-6b31-4967-8dda-cb87b1d7e8b2" xlink:to="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_63b084a9-7464-4a28-a188-1920ff95f232" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_278d95b6-89e7-4c51-aa01-c550757648b0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_63b084a9-7464-4a28-a188-1920ff95f232" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesBalance_278d95b6-89e7-4c51-aa01-c550757648b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_8f151375-0276-473b-8cd6-aad7d8a7e12a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_63b084a9-7464-4a28-a188-1920ff95f232" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_8f151375-0276-473b-8cd6-aad7d8a7e12a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts_f0d419e5-1a99-4718-8903-afd6bf2f9a00" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_63b084a9-7464-4a28-a188-1920ff95f232" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts_f0d419e5-1a99-4718-8903-afd6bf2f9a00" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_05138ba3-5bc1-4734-b78e-f71b6c842c3d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-roles-2023.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AssetsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_us-gaap_OtherAssetsNoncurrent" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract" xlink:to="loc_us-gaap_Liabilities" xlink:type="arc" order="1"/>
  </link:definitionLink>
</link:linkbase>
