-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 WS4wTSND0W5BKlSqDwsMwHuFiVrWzt4RirIwk0Ly5R+Z3GqeMIDZwlgm1VnDbSPM
 DdfgOKB96RBsXZyxnYtmiw==

<SEC-DOCUMENT>0001251309-05-000003.txt : 20050331
<SEC-HEADER>0001251309-05-000003.hdr.sgml : 20050331
<ACCEPTANCE-DATETIME>20050331093643
ACCESSION NUMBER:		0001251309-05-000003
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050329
FILED AS OF DATE:		20050331
DATE AS OF CHANGE:		20050331

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NESTOR INC
		CENTRAL INDEX KEY:			0000720851
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-PREPACKAGED SOFTWARE [7372]
		IRS NUMBER:				133163744
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		400 MASSASOIT AVE
		STREET 2:		STE 200
		CITY:			PROVIDENCE
		STATE:			RI
		ZIP:			02914
		BUSINESS PHONE:		4014345522

	MAIL ADDRESS:	
		STREET 1:		400 MASSASOIT AVE
		STREET 2:		STE 200
		CITY:			PROVIDENCE
		STATE:			RI
		ZIP:			02914

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ALEXANDER BENJAMIN M
		CENTRAL INDEX KEY:			0001251309

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-12965
		FILM NUMBER:		05716624

	BUSINESS ADDRESS:	
		STREET 1:		180 SOUTH MAIN STREET
		CITY:			PROVIDENCE
		STATE:			RI
		ZIP:			02903
		BUSINESS PHONE:		4014345522

	MAIL ADDRESS:	
		STREET 1:		C/O NESTOR, INC.
		STREET 2:		400 MASSASOIT AVENUE, SUITE 200
		CITY:			EAST PROVIDENCE
		STATE:			RI
		ZIP:			02914
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-03-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000720851</issuerCik>
        <issuerName>NESTOR INC</issuerName>
        <issuerTradingSymbol>NESO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001251309</rptOwnerCik>
            <rptOwnerName>ALEXANDER BENJAMIN M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O NESTOR, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>400 MASSASOIT AVENUE, SUITE 200</rptOwnerStreet2>
            <rptOwnerCity>EAST PROVIDENCE</rptOwnerCity>
            <rptOwnerState>RI</rptOwnerState>
            <rptOwnerZipCode>02914</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP, General Counsel &amp; Sec'ty</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>5.95</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-03-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>135000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2013-03-29</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>135000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>135000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Exercisable as to 10,000 shares as of the date of grant,for an additional 15,000 shares on 03/01/2006, for an additional 20,000 shares on 03/01/2007, for an additional 25,000 shares on 03/01/2008, for an additional 30,000 shares on 03/01/2009 and for an additional 35,000 shares on 03/01/2010.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Benjamin M. Alexander</signatureName>
        <signatureDate>2005-03-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----