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        <filer>
          <filerCredentials>
            <cik>0001726596</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
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      <issuerInfo>
        <issuerCik>0000097745</issuerCik>
        <issuerName>THERMO FISHER SCIENTIFIC INC.</issuerName>
        <secFileNumber>001-08002</secFileNumber>
        <issuerAddress>
          <com:street1>168 THIRD AVENUE</com:street1>
          <com:city>WALTHAM</com:city>
          <com:stateOrCountry>MA</com:stateOrCountry>
          <com:zipCode>02451</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>7816221000</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Boxer Michael A</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>3776</noOfUnitsSold>
        <aggregateMarketValue>2010537.49</aggregateMarketValue>
        <noOfUnitsOutstanding>377261182</noOfUnitsOutstanding>
        <approxSaleDate>03/10/2025</approxSaleDate>
        <securitiesExchangeName>NYSE</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/23/2021</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>83</amountOfSecuritiesAcquired>
        <paymentDate>08/23/2021</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/26/2021</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>300</amountOfSecuritiesAcquired>
        <paymentDate>08/26/2021</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/27/2021</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>130</amountOfSecuritiesAcquired>
        <paymentDate>08/27/2021</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/25/2022</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>611</amountOfSecuritiesAcquired>
        <paymentDate>02/25/2022</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/23/2022</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>139</amountOfSecuritiesAcquired>
        <paymentDate>08/23/2022</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/25/2022</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>238</amountOfSecuritiesAcquired>
        <paymentDate>08/25/2022</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/26/2022</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>300</amountOfSecuritiesAcquired>
        <paymentDate>08/26/2022</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/28/2022</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>42</amountOfSecuritiesAcquired>
        <paymentDate>08/28/2022</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/23/2024</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>994</amountOfSecuritiesAcquired>
        <paymentDate>02/23/2024</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/28/2024</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>311</amountOfSecuritiesAcquired>
        <paymentDate>02/28/2024</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/23/2024</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>155</amountOfSecuritiesAcquired>
        <paymentDate>08/23/2024</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/28/2024</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>217</amountOfSecuritiesAcquired>
        <paymentDate>08/28/2024</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/23/2024</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting	</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>256</amountOfSecuritiesAcquired>
        <paymentDate>02/23/2024</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>03/10/2025</noticeDate>
        <signature>/s/ Bradley Camilo, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Michael Boxer</signature>
      </noticeSignature>
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metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 9278}]
text: 144
  0001726596
  XXXXXXXX
  LIVE
  0000097745
  THERMO FISHER SCIENTIFIC INC.
  001-08002
  168 THIRD AVENUE
  WALTHAM
  MA
  02451
  7816221000
  Boxer Michael A
  Officer
  Common
  Fidelity Brokerage Services LLC
  900 Salem Street
  Smithfield
  RI
  02917
  3776
  2010537.49
  377261182
  03/10/2025
  NYSE
  Common
  08/23/2021
  Restricted Stock Vesting
  Issuer
  N
  83
  08/23/2021
  Compensation
  Common
  08/26/2021
  Restricted Stock Vesting
  Issuer
  N
  300
  08/26/2021
  Compensation
  Common
  08/27/2021
  Restricted Stock Vesting
  Issuer
  N
  130
  08/27/2021
  Compensation
  Common
  02/25/2022
  Restricted Stock Vesting
  Issuer
  N
  611
  02/25/2022
  Compensation
  Common
  08/23/2022
  Restricted Stock Vesting
  Issuer
  N
  139
  08/23/2022
  Compensation
  Common
  08/25/2022
  Restricted Stock Vesting
  Issuer
  N
  238
  08/25/2022
  Compensation
  Common
  08/26/2022
  Restricted Stock Vesting
  Issuer
  N
  300
  08/26/2022
  Compensation
  Common
  08/28/2022
  Restricted Stock Vesting
  Issuer
  N
  42
  08/28/2022
  Compensation
  Common
  02/23/2024
  Restricted Stock Vesting
  Issuer
  N
  994
  02/23/2024
  Compensation
  Common
  02/28/2024
  Restricted Stock Vesting
  Issuer
  N
  311
  02/28/2024
  Compensation
  Common
  08/23/2024
  Restricted Stock Vesting
  Issuer
  N
  155
  08/23/2024
  Compensation
  Common
  08/28/2024
  Restricted Stock Vesting
  Issuer
  N
  217
  08/28/2024
  Compensation
  Common
  02/23/2024
  Restricted Stock Vesting
  Issuer
  N
  256
  02/23/2024
  Compensation
  Y
  03/10/2025
  /s/ Bradley Camilo, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Michael Boxer