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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 TNVNsEifK/lNRuNQPdu3NX6ttHi/moMRKYff86yEaJHy+W26zVFxo0Y1Fp2pSSvR
 KU47u3DkWJttfcSVJvFiKw==

<SEC-DOCUMENT>0001179110-07-019220.txt : 20071002
<SEC-HEADER>0001179110-07-019220.hdr.sgml : 20071002
<ACCEPTANCE-DATETIME>20071002172752
ACCESSION NUMBER:		0001179110-07-019220
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20071001
FILED AS OF DATE:		20071002
DATE AS OF CHANGE:		20071002

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MATHSTAR INC
		CENTRAL INDEX KEY:			0001118037
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			MN
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		19075 NORTHWEST TANASBOURNE DRIVE
		STREET 2:		SUITE 200
		CITY:			HILLSBORO
		STATE:			OR
		ZIP:			97124
		BUSINESS PHONE:		503-726-5500

	MAIL ADDRESS:	
		STREET 1:		19075 NORTHWEST TANASBOURNE DRIVE
		STREET 2:		SUITE 200
		CITY:			HILLSBORO
		STATE:			OR
		ZIP:			97124

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Corvese Russell E
		CENTRAL INDEX KEY:			0001413743

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51560
		FILM NUMBER:		071150994

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		503-726-5500

	MAIL ADDRESS:	
		STREET 1:		19075 NW TANASBOURNE DRIVE
		STREET 2:		SUITE 200
		CITY:			HILLSBOROR
		STATE:			OR
		ZIP:			97124
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 3 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2007-10-01</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001118037</issuerCik>
        <issuerName>MATHSTAR INC</issuerName>
        <issuerTradingSymbol>MATH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001413743</rptOwnerCik>
            <rptOwnerName>Corvese Russell E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>19075 NW TANASBOURNE DRIVE #200</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HILLSBORO</rptOwnerCity>
            <rptOwnerState>OR</rptOwnerState>
            <rptOwnerZipCode>97124</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP of Sales</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.07</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2017-09-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>350000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Stock Option was granted on October 1, 2007 and vests one-fourth annually from the grant date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>James W. Cruckshank, by power of attorney</signatureName>
        <signatureDate>2007-10-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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