<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-01-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000097745</issuerCik>
        <issuerName>THERMO FISHER SCIENTIFIC INC.</issuerName>
        <issuerTradingSymbol>TMO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001033876</rptOwnerCik>
            <rptOwnerName>MEISTER PAUL M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>81 WYMAN STREET</rptOwnerStreet1>
            <rptOwnerStreet2>P.O. BOX 9046</rptOwnerStreet2>
            <rptOwnerCity>WALTHAM</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>024549046</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-01-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>190050</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>45.17</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>702950.00</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-01-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>200000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.62</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>902950.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-01-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>200000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>45.29</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>702950.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-01-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>177512</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.62</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>880462.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-01-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>255462</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>45.50</value>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>625000.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>19.62</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-01-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>200000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2006-11-09</value>
            </exerciseDate>
            <expirationDate>
                <value>2008-09-26</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>200000.00</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>177512.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>19.62</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-01-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>177512</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2006-11-09</value>
            </exerciseDate>
            <expirationDate>
                <value>2008-09-26</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>177512.00</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Includes 352,950 shares previously held indirectly through a trust for the benefit of the reporting person, and that were distributed to the reporting person effective as of January 3, 2007, and are now owned directly.</footnote>
        <footnote id="F2">The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 13, 2006.</footnote>
        <footnote id="F3">The sales price shown is the average sales price for all shares sold on January 3, 2007, actual denominations are as follows: 50,000 shares at $45.05; 100,000 shares at $45.25; 23,400 shares at $45.52; 25,000 shares at $45.70 and 1,600 shares at $45.75.</footnote>
        <footnote id="F4">The sales price shown is the average sales price for all shares sold on January 4, 2007, actual denominations are as follows: 53,800 shares at $45.30; 4,500 shares at $45.31; 100 shares at $45.33; 1,600 shares at $45.35; 2,400 shares at $45.36; 2,300 shares at $45.37; 2,000 shares at $45.38; 1,300 shares at $45.39; 2,000 shares at $45.40; 2,500 shares at $45.41; 800 shares at $45.42; 1,500 shares at $45.45; 200 shares at $45.46; 73,547 shares at $45.50; 9,300 shares at $45.51; 7,000 shares at $45.52; 3,700 shares at $45.53; 3,800 shares at $45.54; 2,700 shares at $45.55; 400 shares at $45.56; 5,715 shares at $45.57; 700 shares at $45.58; 2,202 shares at $45.62; 12,798 shares at $45.63; 12,600 shares at $45.65; 4,700 shares at $45.66; 2,200 shares at $45.67; 35,400 shares at $45.68; 2,900 shares at $45.69; 300 shares at $45.70 and 500 shares at $45.71.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>By: Barbara J. Lucas, Attorney-in-Fact for Paul M. Meister</signatureName>
        <signatureDate>2007-01-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2007-01-03
0
0000097745
THERMO FISHER SCIENTIFIC INC.
TMO
0001033876
MEISTER PAUL M
81 WYMAN STREET
P.O. BOX 9046
WALTHAM
MA
024549046
1
0
0
0
Common Stock
2007-01-03
4
F
0
190050
45.17
D
702950.00
D
Common Stock
2007-01-03
4
M
0
200000
19.62
A
902950.00
D
Common Stock
2007-01-03
4
S
0
200000
45.29
D
702950.00
D
Common Stock
2007-01-04
4
M
0
177512
19.62
A
880462.00
D
Common Stock
2007-01-04
4
S
0
255462
45.50
D
625000.00
D
Stock Option (Right to Buy)
19.62
2007-01-03
4
M
0
200000
0
D
2006-11-09
2008-09-26
Common Stock
200000.00
177512.00
D
Stock Option (Right to Buy)
19.62
2007-01-04
4
M
0
177512
0
D
2006-11-09
2008-09-26
Common Stock
177512.00
0.00
D
Includes 352,950 shares previously held indirectly through a trust for the benefit of the reporting person, and that were distributed to the reporting person effective as of January 3, 2007, and are now owned directly.
The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 13, 2006.
The sales price shown is the average sales price for all shares sold on January 3, 2007, actual denominations are as follows: 50,000 shares at $45.05; 100,000 shares at $45.25; 23,400 shares at $45.52; 25,000 shares at $45.70 and 1,600 shares at $45.75.
The sales price shown is the average sales price for all shares sold on January 4, 2007, actual denominations are as follows: 53,800 shares at $45.30; 4,500 shares at $45.31; 100 shares at $45.33; 1,600 shares at $45.35; 2,400 shares at $45.36; 2,300 shares at $45.37; 2,000 shares at $45.38; 1,300 shares at $45.39; 2,000 shares at $45.40; 2,500 shares at $45.41; 800 shares at $45.42; 1,500 shares at $45.45; 200 shares at $45.46; 73,547 shares at $45.50; 9,300 shares at $45.51; 7,000 shares at $45.52; 3,700 shares at $45.53; 3,800 shares at $45.54; 2,700 shares at $45.55; 400 shares at $45.56; 5,715 shares at $45.57; 700 shares at $45.58; 2,202 shares at $45.62; 12,798 shares at $45.63; 12,600 shares at $45.65; 4,700 shares at $45.66; 2,200 shares at $45.67; 35,400 shares at $45.68; 2,900 shares at $45.69; 300 shares at $45.70 and 500 shares at $45.71.
By: Barbara J. Lucas, Attorney-in-Fact for Paul M. Meister
2007-01-05