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Proc-Type: 2001,MIC-CLEAR
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<SEC-DOCUMENT>0001455754-11-000026.txt : 20110211
<SEC-HEADER>0001455754-11-000026.hdr.sgml : 20110211
<ACCEPTANCE-DATETIME>20110211142430
ACCESSION NUMBER:		0001455754-11-000026
CONFORMED SUBMISSION TYPE:	5
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20101231
FILED AS OF DATE:		20110211
DATE AS OF CHANGE:		20110211

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			DIETRICH MARTIN A
		CENTRAL INDEX KEY:			0001204704

	FILING VALUES:
		FORM TYPE:		5
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-14703
		FILM NUMBER:		11598016

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NBT BANCORP INC
		CENTRAL INDEX KEY:			0000790359
		STANDARD INDUSTRIAL CLASSIFICATION:	NATIONAL COMMERCIAL BANKS [6021]
		IRS NUMBER:				161268674
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		52 S BROAD ST
		CITY:			NORWICH
		STATE:			NY
		ZIP:			13815
		BUSINESS PHONE:		6073372265

	MAIL ADDRESS:	
		STREET 1:		52 S. BROAD STREET
		CITY:			NORWICH
		STATE:			NY
		ZIP:			13815
</SEC-HEADER>
<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>2010-12-31</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>0001204704</rptOwnerCik>
            <rptOwnerName>DIETRICH MARTIN 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>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President &amp; CEO NBT Bancorp</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
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            <securityTitle>
                <value>NBT Bancorp Inc. Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-12-31</value>
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            <transactionCoding>
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                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionAmounts>
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                <transactionPricePerShare>
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                <transactionAcquiredDisposedCode>
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                    <value>59623.451</value>
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        <nonDerivativeTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>401k</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
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                <value>NBT Bancorp Inc. Common Stock</value>
            </securityTitle>
            <transactionDate>
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            <transactionCoding>
                <transactionFormType>5</transactionFormType>
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                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionAmounts>
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                </transactionShares>
                <transactionPricePerShare>
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            <ownershipNature>
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                <natureOfOwnership>
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        <nonDerivativeHolding>
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                <value>NBT Bancorp Inc. Common Stock</value>
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            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Spouse</value>
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            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
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                <value>14.3492</value>
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            <exerciseDate>
                <value>2003-01-28</value>
            </exerciseDate>
            <expirationDate>
                <value>2012-01-28</value>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>NBT Bancorp Inc. Common Stock</value>
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                <underlyingSecurityShares>
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            <ownershipNature>
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                    <value>D</value>
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        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Non-Qualified Stock Option (right to buy)</value>
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            <conversionOrExercisePrice>
                <value>17.538</value>
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            <exerciseDate>
                <value>2004-01-01</value>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <value>2013-01-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>NBT Bancorp Inc. Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
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            </underlyingSecurity>
            <postTransactionAmounts>
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                    <value>D</value>
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        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Non-Qualified Stock Option (right to buy)</value>
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            <conversionOrExercisePrice>
                <value>20.19</value>
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            <exerciseDate>
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                <footnoteId id="F5"/>
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            <expirationDate>
                <value>2020-01-15</value>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>NBT Bancorp Inc. Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
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            </underlyingSecurity>
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        <derivativeHolding>
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                <value>20.3617</value>
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            <exerciseDate>
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                <footnoteId id="F4"/>
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            <expirationDate>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>NBT Bancorp Inc. Common Stock</value>
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                <underlyingSecurityShares>
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            <securityTitle>
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            <conversionOrExercisePrice>
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            <exerciseDate>
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            <expirationDate>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
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                <value>2017-12-27</value>
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                <value>25.38</value>
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                <value>2010-01-15</value>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2019-01-15</value>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>NBT Bancorp Inc. Common Stock</value>
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                <directOrIndirectOwnership>
                    <value>D</value>
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        <derivativeHolding>
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                <value>2008-01-01</value>
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                <value>2017-01-01</value>
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            <underlyingSecurity>
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                    <value>NBT Bancorp Inc. Common Stock</value>
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                <underlyingSecurityShares>
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                    <value>D</value>
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    </derivativeTable>

    <footnotes>
        <footnote id="F1">Shares acquired under NBT Bancorp Dividend Reinvestment Plan during period of January 1, 2010 to December 31, 2010 at prices ranging from $21.4584 to $24.25 per share.</footnote>
        <footnote id="F2">Shares were purchased from 1/1/2010 through 12/31/2010 through NBT Bancorp Inc. 401k Plan.</footnote>
        <footnote id="F3">Shares were purchased from 1/1/2010 through 12/31/2010 through NBT Bancorp Inc. ESOP Plan.</footnote>
        <footnote id="F4">Pursuant to NBT Bancorp Inc. 1993 Stock Option Plan grant vests 40% for first year, 20% annually for following years.</footnote>
        <footnote id="F5">Pursuant to NBT Bancorp Inc. Omnibus Stock Option Agreement the grant vests 40% for first year, 20% annually for following years.</footnote>
        <footnote id="F6">Pursuant to NBT Bancorp Inc. 1993 Stock Option Plan reload grant vests 100% two years after date of its grant.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: F. Sheldon Prentice, Power of Attorney  For: Martin A Dietrich</signatureName>
        <signatureDate>2011-02-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----