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>0001654667</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>4148795000</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Chiarello Guy</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Officer</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>COMMON</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>MERRILL LYNCH</name>
          <address>
            <com:street1>3455 PEACHTREE RD NE</com:street1>
            <com:street2>SUITE 1000</com:street2>
            <com:city>ATLANTA</com:city>
            <com:stateOrCountry>GA</com:stateOrCountry>
            <com:zipCode>30326</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>24000</noOfUnitsSold>
        <aggregateMarketValue>3959278.78</aggregateMarketValue>
        <noOfUnitsOutstanding>575725190</noOfUnitsOutstanding>
        <approxSaleDate>08/15/2024</approxSaleDate>
        <securitiesExchangeName>NEW YORK</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>COMMON</securitiesClassTitle>
        <acquiredDate>08/15/2024</acquiredDate>
        <natureOfAcquisitionTransaction>EXERCISE OF STOCK OPTIONS</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>FISERV INC.</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>24000</amountOfSecuritiesAcquired>
        <paymentDate>08/15/2024</paymentDate>
        <natureOfPayment>COMPENSATORY PAYMENT</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>GUY CHIARELLO</name>
          <address>
            <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>
          </address>
        </sellerDetails>
        <securitiesClassTitle>COMMON</securitiesClassTitle>
        <saleDate>06/17/2024</saleDate>
        <amountOfSecuritiesSold>24000</amountOfSecuritiesSold>
        <grossProceeds>3563225.47</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>GUY CHIARELLO</name>
          <address>
            <com:street1>600 N. VEL R. PHILLIPS AVENUE</com:street1>
            <com:city>MILWAUKE</com:city>
            <com:stateOrCountry>WI</com:stateOrCountry>
            <com:zipCode>53203</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>COMMON</securitiesClassTitle>
        <saleDate>05/15/2024</saleDate>
        <amountOfSecuritiesSold>24000</amountOfSecuritiesSold>
        <grossProceeds>3709404.17</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>GUY CHIARELLO</name>
          <address>
            <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>
          </address>
        </sellerDetails>
        <securitiesClassTitle>COMMON</securitiesClassTitle>
        <saleDate>07/15/2024</saleDate>
        <amountOfSecuritiesSold>24000</amountOfSecuritiesSold>
        <grossProceeds>3716537.81</grossProceeds>
      </securitiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>08/15/2024</noticeDate>
        <planAdoptionDates>
          <planAdoptionDate>12/15/2023</planAdoptionDate>
        </planAdoptionDates>
        <signature>GUY CHIARELLO</signature>
      </noticeSignature>
    </formData>
  </edgarSubmission>
metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 4661}]
text: 144
  0001654667
  XXXXXXXX
  LIVE
  0000798354
  FISERV INC
  001-38962
  600 N. VEL R. PHILLIPS AVENUE
  MILWAUKEE
  WI
  53203
  4148795000
  Chiarello Guy
  Officer
  COMMON
  MERRILL LYNCH
  3455 PEACHTREE RD NE
  SUITE 1000
  ATLANTA
  GA
  30326
  24000
  3959278.78
  575725190
  08/15/2024
  NEW YORK
  COMMON
  08/15/2024
  EXERCISE OF STOCK OPTIONS
  FISERV INC.
  N
  24000
  08/15/2024
  COMPENSATORY PAYMENT
  N
  GUY CHIARELLO
  600 N. VEL R. PHILLIPS AVENUE
  MILWAUKEE
  WI
  53203
  COMMON
  06/17/2024
  24000
  3563225.47
  GUY CHIARELLO
  600 N. VEL R. PHILLIPS AVENUE
  MILWAUKE
  WI
  53203
  COMMON
  05/15/2024
  24000
  3709404.17
  GUY CHIARELLO
  600 N. VEL R. PHILLIPS AVENUE
  MILWAUKEE
  WI
  53203
  COMMON
  07/15/2024
  24000
  3716537.81
  08/15/2024
  12/15/2023
  GUY CHIARELLO