content: <?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
    <headerData>
      <submissionType>144</submissionType>
      <filerInfo>
        <filer>
          <filerCredentials>
            <cik>0001407947</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
      </filerInfo>
    </headerData>
    <formData>
      <issuerInfo>
        <issuerCik>0000798354</issuerCik>
        <issuerName>FISERV INC</issuerName>
        <secFileNumber>001-38962</secFileNumber>
        <issuerAddress>
          <com:street1>600 N. VEL R. PHILLIPS AVENUE</com:street1>
          <com:city>MILWAUKEE</com:city>
          <com:stateOrCountry>WI</com:stateOrCountry>
          <com:zipCode>53203</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>2628795000</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Best Kenneth</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Officer</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>Fidelity Brokerage Services LLC</name>
          <address>
            <com:street1>900 Salem Street</com:street1>
            <com:city>Smithfield</com:city>
            <com:stateOrCountry>RI</com:stateOrCountry>
            <com:zipCode>02917</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>20821</noOfUnitsSold>
        <aggregateMarketValue>4468372.22</aggregateMarketValue>
        <noOfUnitsOutstanding>568918735</noOfUnitsOutstanding>
        <approxSaleDate>11/12/2024</approxSaleDate>
        <securitiesExchangeName>NYSE</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>11/12/2024</acquiredDate>
        <natureOfAcquisitionTransaction>Option Granted 02/22/2017</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>4570</amountOfSecuritiesAcquired>
        <paymentDate>11/12/2024</paymentDate>
        <natureOfPayment>Cash</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>11/12/2024</acquiredDate>
        <natureOfAcquisitionTransaction>Option Granted 02/21/2018</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>6698</amountOfSecuritiesAcquired>
        <paymentDate>11/12/2024</paymentDate>
        <natureOfPayment>Cash</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>11/12/2024</acquiredDate>
        <natureOfAcquisitionTransaction>Option Granted 02/20/2019</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>5277</amountOfSecuritiesAcquired>
        <paymentDate>11/12/2024</paymentDate>
        <natureOfPayment>Cash</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>11/12/2024</acquiredDate>
        <natureOfAcquisitionTransaction>Option Granted 02/26/2020</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>4276</amountOfSecuritiesAcquired>
        <paymentDate>11/12/2024</paymentDate>
        <natureOfPayment>Cash</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>11/12/2024</noticeDate>
        <signature>/s/ Eric Janiak, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Kenneth F. Best</signature>
      </noticeSignature>
    </formData>
  </edgarSubmission>
metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 4415}]
text: 144
  0001407947
  XXXXXXXX
  LIVE
  0000798354
  FISERV INC
  001-38962
  600 N. VEL R. PHILLIPS AVENUE
  MILWAUKEE
  WI
  53203
  2628795000
  Best Kenneth
  Officer
  Common
  Fidelity Brokerage Services LLC
  900 Salem Street
  Smithfield
  RI
  02917
  20821
  4468372.22
  568918735
  11/12/2024
  NYSE
  Common
  11/12/2024
  Option Granted 02/22/2017
  Issuer
  N
  4570
  11/12/2024
  Cash
  Common
  11/12/2024
  Option Granted 02/21/2018
  Issuer
  N
  6698
  11/12/2024
  Cash
  Common
  11/12/2024
  Option Granted 02/20/2019
  Issuer
  N
  5277
  11/12/2024
  Cash
  Common
  11/12/2024
  Option Granted 02/26/2020
  Issuer
  N
  4276
  11/12/2024
  Cash
  Y
  11/12/2024
  /s/ Eric Janiak, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Kenneth F. Best