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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-12-01</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>2006-12-01</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>250000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>43.64</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>386787.00</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-12-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>240725</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.75</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>627512.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-12-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>122488</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.62</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>750000.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-12-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>400000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>44.04</value>
                    <footnoteId id="F4"/>
                </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>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-12-05</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>100000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.62</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</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>2006-12-05</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>44.42</value>
                    <footnoteId id="F5"/>
                </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>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>543000.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.75</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2006-12-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>240725</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2006-11-09</value>
            </exerciseDate>
            <expirationDate>
                <value>2008-01-21</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>240725.00</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0.00</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>2006-12-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>122488</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>122488.00</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>477512.00</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>2006-12-05</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>100000</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>100000.00</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>377512.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <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 price is the average price for all shares sold on 12/1/06, actual amounts are as follows:3,400 shares @ $43.25; 100 shares @ $43.30; 200 shares @ $43.31; 400 shares @ $43.32; 100 shares @ $43.33; 100 shares @ $43.34; 5,400 shares @ $43.35; 200 shares @ $43.36; 2,600 shares @ $43.37;  2,600 shares @ $43.38; 500 shares @ $43.39; 1,700 shares @ $43.40; 300 shares @ $43.42; 11,200 shares @ $43.43; 4,200 shares @ $43.44; 5,800 shares @ $43.45; 500 shares @ $43.46; 300 shares @ $43.47; 500 shares @ $43.48; 19,600 shares @ $43.49; 24,800 shares @ $43.50; 1,600 shares @ $43.51; 1,300 shares @ $43.52; 1,800 shares @ $43.53; 1,400 shares @ $43.54; 500 shares @ $43.55; 1,200 shares @ $43.56; 1,300 shares @ $43.57; 200 shares @ $43.58; 1,000 shares @ $43.59; 50,400 shares @ $43.60; 4,800 shares @ $43.64; 10,000 shares @ $43.70; 10,000 shares @ $43.73; 10,000 shares @ $43.74; 20,000 shares @ $43.78; 2,000 shares @ $43.87; 18,000 shares @ $43.89; 23,100 shares @ $43.90; 6,900 shares @ $43.91.</footnote>
        <footnote id="F3">Includes 286,787 shares previously held indirectly through trusts for the benefit of the reporting person, and that were distributed to the reporting person effective as of November 10, 2006, and are now owned directly. See Footnote 6.</footnote>
        <footnote id="F4">The price is the average price for all shares sold on 12/4/06, actual amounts are as follows:10,500 shares @ $43.90; 2,200 shares @ $43.93; 2,300 shares @ $43.96; 1,100 shares @ $43.97; 6,900 shares @ $43.98; 2,000 shares @ $43.99; 164,800 shares @ $44.00; 60,100 shares @ $44.02; 50,100 shares @ $44.05;  50,000 shares @ $44.06; 3,500 shares @ $44.12; 3,200 shares @ $44.13; 1,000 shares @ $44.20; 5,000 shares @ $44.21; 5,000 shares @ $44.22; 2,500 shares @ $44.23; 29,800 shares @ $44.24.</footnote>
        <footnote id="F5">The price is the average price for all shares sold on 12/5/06, actual amounts are as follows: 300 shares @ $44.06; 1,100 shares @ $44.08; 300 shares @ $44.11; 1,000 shares @ $44.12; 400 shares @ $44.13; 100 shares @ $44.14; 6,800 shares @ $44.15; 10,000 shares @ $44.20; 100 shares @ $44.32;  200 shares @ $44.33; 2,100 shares @ $44.34; 2,600 shares @ $44.35; 3,700 shares @ $44.38; 400 shares @ $44.39; 25,900 shares @ $44.40; 20,000 shares @ $44.50; 100 shares @ $44.53; 2,700 shares @ $44.54; 2,200 shares @ $44.55; 10,000 shares @ $44.60; 10,000 shares @ $44.65.</footnote>
        <footnote id="F6">Reflects distribution to the reporting person of 286,787 shares held in trusts for the benefit of the reporting person effective as of November 10, 2006, and now owned directly.  See Footnote 3.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>By: Barbara J. Lucas, Attorney-in-Fact for Paul M. Meister</signatureName>
        <signatureDate>2006-12-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
[{"type": "4", "sequence": "1", "filename": "mei440.xml", "secsgml_size_bytes": 21251}]
X0202
4
2006-12-01
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
2006-12-01
4
S
0
250000
43.64
D
386787.00
D
Common Stock
2006-12-04
4
M
0
240725
4.75
A
627512.00
D
Common Stock
2006-12-04
4
M
0
122488
19.62
A
750000.00
D
Common Stock
2006-12-04
4
S
0
400000
44.04
D
350000.00
D
Common Stock
2006-12-05
4
M
0
100000
19.62
A
450000.00
D
Common Stock
2006-12-05
4
S
0
100000
44.42
D
350000.00
D
Common Stock
543000.00
I
By Trust
Stock Option (Right to Buy)
4.75
2006-12-04
4
M
0
240725
0
D
2006-11-09
2008-01-21
Common Stock
240725.00
0.00
D
Stock Option (Right to Buy)
19.62
2006-12-04
4
M
0
122488
0
D
2006-11-09
2008-09-26
Common Stock
122488.00
477512.00
D
Stock Option (Right to Buy)
19.62
2006-12-05
4
M
0
100000
0
D
2006-11-09
2008-09-26
Common Stock
100000.00
377512.00
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 price is the average price for all shares sold on 12/1/06, actual amounts are as follows:3,400 shares @ $43.25; 100 shares @ $43.30; 200 shares @ $43.31; 400 shares @ $43.32; 100 shares @ $43.33; 100 shares @ $43.34; 5,400 shares @ $43.35; 200 shares @ $43.36; 2,600 shares @ $43.37;  2,600 shares @ $43.38; 500 shares @ $43.39; 1,700 shares @ $43.40; 300 shares @ $43.42; 11,200 shares @ $43.43; 4,200 shares @ $43.44; 5,800 shares @ $43.45; 500 shares @ $43.46; 300 shares @ $43.47; 500 shares @ $43.48; 19,600 shares @ $43.49; 24,800 shares @ $43.50; 1,600 shares @ $43.51; 1,300 shares @ $43.52; 1,800 shares @ $43.53; 1,400 shares @ $43.54; 500 shares @ $43.55; 1,200 shares @ $43.56; 1,300 shares @ $43.57; 200 shares @ $43.58; 1,000 shares @ $43.59; 50,400 shares @ $43.60; 4,800 shares @ $43.64; 10,000 shares @ $43.70; 10,000 shares @ $43.73; 10,000 shares @ $43.74; 20,000 shares @ $43.78; 2,000 shares @ $43.87; 18,000 shares @ $43.89; 23,100 shares @ $43.90; 6,900 shares @ $43.91.
Includes 286,787 shares previously held indirectly through trusts for the benefit of the reporting person, and that were distributed to the reporting person effective as of November 10, 2006, and are now owned directly. See Footnote 6.
The price is the average price for all shares sold on 12/4/06, actual amounts are as follows:10,500 shares @ $43.90; 2,200 shares @ $43.93; 2,300 shares @ $43.96; 1,100 shares @ $43.97; 6,900 shares @ $43.98; 2,000 shares @ $43.99; 164,800 shares @ $44.00; 60,100 shares @ $44.02; 50,100 shares @ $44.05;  50,000 shares @ $44.06; 3,500 shares @ $44.12; 3,200 shares @ $44.13; 1,000 shares @ $44.20; 5,000 shares @ $44.21; 5,000 shares @ $44.22; 2,500 shares @ $44.23; 29,800 shares @ $44.24.
The price is the average price for all shares sold on 12/5/06, actual amounts are as follows: 300 shares @ $44.06; 1,100 shares @ $44.08; 300 shares @ $44.11; 1,000 shares @ $44.12; 400 shares @ $44.13; 100 shares @ $44.14; 6,800 shares @ $44.15; 10,000 shares @ $44.20; 100 shares @ $44.32;  200 shares @ $44.33; 2,100 shares @ $44.34; 2,600 shares @ $44.35; 3,700 shares @ $44.38; 400 shares @ $44.39; 25,900 shares @ $44.40; 20,000 shares @ $44.50; 100 shares @ $44.53; 2,700 shares @ $44.54; 2,200 shares @ $44.55; 10,000 shares @ $44.60; 10,000 shares @ $44.65.
Reflects distribution to the reporting person of 286,787 shares held in trusts for the benefit of the reporting person effective as of November 10, 2006, and now owned directly.  See Footnote 3.
By: Barbara J. Lucas, Attorney-in-Fact for Paul M. Meister
2006-12-05