-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 LGupfZlbQKqLdzW/YKgARtb0WY5sjIbx+Iw68/ELpvPCmVeDum/AGxe0V83ghSnl
 7wX4v98aK5tGxzeIj71Bjg==

<SEC-DOCUMENT>0000908662-05-000272.txt : 20051031
<SEC-HEADER>0000908662-05-000272.hdr.sgml : 20051031
<ACCEPTANCE-DATETIME>20051031153959
ACCESSION NUMBER:		0000908662-05-000272
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20051027
FILED AS OF DATE:		20051031
DATE AS OF CHANGE:		20051031

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ENTERPRISE BANCORP INC /MA/
		CENTRAL INDEX KEY:			0001018399
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		222 MERRIMACK ST
		CITY:			LOWELL
		STATE:			MA
		ZIP:			01852
		BUSINESS PHONE:		9784599000

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ANSIN KEN S
		CENTRAL INDEX KEY:			0001282759

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	333-79135
		FILM NUMBER:		051166356

	BUSINESS ADDRESS:	
		STREET 1:		390 GOODRICH STREET
		STREET 2:		-
		CITY:			LUNENBURG
		STATE:			MA
		ZIP:			01462

	MAIL ADDRESS:	
		STREET 1:		390 GOODRICH ST
		CITY:			LUNENBURG
		STATE:			MA
		ZIP:			01462
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-10-27</periodOfReport>

    <issuer>
        <issuerCik>0001018399</issuerCik>
        <issuerName>ENTERPRISE BANCORP INC /MA/</issuerName>
        <issuerTradingSymbol>EBTC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001282759</rptOwnerCik>
            <rptOwnerName>ANSIN KEN S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ENTERPRISE BANCORP INC</rptOwnerStreet1>
            <rptOwnerStreet2>222 MERRIMACK STREET</rptOwnerStreet2>
            <rptOwnerCity>LOWELL</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01852</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>2005-10-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>100</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>27.50</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>51073.8969</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>500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust for son G. Ansin</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust for son K. Ansin</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Richard W. Main as attorney-in-fact</signatureName>
        <signatureDate>2005-10-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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