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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-01-05</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>2007-01-05</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>175000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>45.36</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>450000.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-01-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>100000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>44.97</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>350000.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">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="F2">The sales price shown is the average sales price for all shares sold on January 5, 2007, actual denominations are as follows: 900 shares at $44.95; 800 shares at $44.96; 600 shares at $44.97; 21,300 shares at $45.00; 6,100 shares at $45.01; 1,800 shares at $45.02; 15,300 shares at $45.05; 400 shares at $45.06; 2,400 shares at $45.07; 6,600 shares at $45.08; 300 shares at $45.09; 77,300 shares at $45.50; 200 shares at $45.52; 200 shares at $45.53; 36,300 shares at $45.55; 3,500 shares at $45.56; 600 shares at $45.58; and 400 shares at $45.59.</footnote>
        <footnote id="F3">The sales price shown is the average sales price for all shares sold on January 8, 2007, actual denominations are as follows: 12,400 shares at $44.90; 1,400 shares at $44.91; 2,800 shares at $44.92; 15,500 shares at $44.93; 500 shares at $44.94; 40,800 shares at $44.95; 1,900 shares at $44.97; 4,700 shares at $45.00; and 20,000 shares at $45.10.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>By: Barbara J. Lucas, Attorney-in-Fact for Paul M. Meister</signatureName>
        <signatureDate>2007-01-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2007-01-05
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
2007-01-05
4
S
0
175000
45.36
D
450000.00
D
Common Stock
2007-01-08
4
S
0
100000
44.97
D
350000.00
D
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 5, 2007, actual denominations are as follows: 900 shares at $44.95; 800 shares at $44.96; 600 shares at $44.97; 21,300 shares at $45.00; 6,100 shares at $45.01; 1,800 shares at $45.02; 15,300 shares at $45.05; 400 shares at $45.06; 2,400 shares at $45.07; 6,600 shares at $45.08; 300 shares at $45.09; 77,300 shares at $45.50; 200 shares at $45.52; 200 shares at $45.53; 36,300 shares at $45.55; 3,500 shares at $45.56; 600 shares at $45.58; and 400 shares at $45.59.
The sales price shown is the average sales price for all shares sold on January 8, 2007, actual denominations are as follows: 12,400 shares at $44.90; 1,400 shares at $44.91; 2,800 shares at $44.92; 15,500 shares at $44.93; 500 shares at $44.94; 40,800 shares at $44.95; 1,900 shares at $44.97; 4,700 shares at $45.00; and 20,000 shares at $45.10.
By: Barbara J. Lucas, Attorney-in-Fact for Paul M. Meister
2007-01-09