<SUBMISSION>
<ACCESSION-NUMBER>0001320922-09-000021
<TYPE>5
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20081231
<FILING-DATE>20090126
<DATE-OF-FILING-DATE-CHANGE>20090126
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>NBT BANCORP INC
<CIK>0000790359
<ASSIGNED-SIC>6021
<IRS-NUMBER>161268674
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>52 S BROAD ST
<CITY>NORWICH
<STATE>NY
<ZIP>13815
<PHONE>6073372265
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>52 S. BROAD STREET
<CITY>NORWICH
<STATE>NY
<ZIP>13815
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>Wadsworth Robert A
<CIK>0001380360
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>5
<ACT>34
<FILE-NUMBER>000-14703
<FILM-NUMBER>09545488
</FILING-VALUES>
<BUSINESS-ADDRESS>
<PHONE>607-847-6161
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>52 SOUTH BROAD STREET
<CITY>NORWICH
<STATE>NY
<ZIP>13815
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>5
<SEQUENCE>1
<FILENAME>edgardoc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2008-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

    <issuer>
        <issuerCik>0000790359</issuerCik>
        <issuerName>NBT BANCORP INC</issuerName>
        <issuerTradingSymbol>NBTB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001380360</rptOwnerCik>
            <rptOwnerName>Wadsworth Robert A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>52 SOUTH BROAD STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NORWICH</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>13815</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>NBT Bancorp Inc. Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>45.985</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3999.176</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>NBT Bancorp Inc. Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>164041</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Corporation</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Non-Qualified Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>21.74</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2007-05-01</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2016-05-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>NBT Bancorp Inc. Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Non-Qualified Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>22.4092</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2007-01-01</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2016-01-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>NBT Bancorp Inc. Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>210</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>210</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Non-Qualified Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>22.4842</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2008-05-01</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2017-05-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>NBT Bancorp Inc. Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1375</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1375</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Non-Qualified Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>22.5508</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2009-05-01</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2018-05-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>NBT Bancorp Inc. Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1625</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1625</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Non-Qualified Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>24.08</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2007-11-10</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2016-11-10</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>NBT Bancorp Inc. Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Shares acquired under NBT Bancorp Dividend Reinvestment Plan during period of January 1, 2008 to December 31, 2008 at prices ranging from $21.1468 to $26.8782 per share.</footnote>
        <footnote id="F2">Pursuant to NBT Non-Employee Director, Divisional Director and Subsidiary Director Stock Option Plan grant vests 40% for first year, 20% annually for following years.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: Michael J. Chewens, Power of Attorney  For: Robert Wadsworth</signatureName>
        <signatureDate>2009-01-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
