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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0000855658-05-000011.txt : 20050811
<SEC-HEADER>0000855658-05-000011.hdr.sgml : 20050811
<ACCEPTANCE-DATETIME>20050811180720
ACCESSION NUMBER:		0000855658-05-000011
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050809
FILED AS OF DATE:		20050811
DATE AS OF CHANGE:		20050811

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			LATTICE SEMICONDUCTOR CORP
		CENTRAL INDEX KEY:			0000855658
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				930835214
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0101

	BUSINESS ADDRESS:	
		STREET 1:		5555 NE MOORE COURT
		CITY:			HILLSBORO
		STATE:			OR
		ZIP:			97124-6421
		BUSINESS PHONE:		5032688000

	MAIL ADDRESS:	
		STREET 1:		5555 NE MOORE COURT
		CITY:			HILLSBORO
		STATE:			OR
		ZIP:			97124

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BAKER MARTIN RAYMOND
		CENTRAL INDEX KEY:			0001224178

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-18032
		FILM NUMBER:		051018466

	MAIL ADDRESS:	
		STREET 1:		5555 NE MOORE CT.
		CITY:			HILLSBORO
		STATE:			OR
		ZIP:			97124
</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>2005-08-09</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000855658</issuerCik>
        <issuerName>LATTICE SEMICONDUCTOR CORP</issuerName>
        <issuerTradingSymbol>LSCC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001224178</rptOwnerCik>
            <rptOwnerName>BAKER MARTIN RAYMOND</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5555 NE MOORE CT.</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>Vice President,General Counsel</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Employee Option to Buy</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.56</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-08-09</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>45000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2005-11-09</value>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2015-08-09</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>45000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>45000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This option to purchase shares of common stock vests as follows: 6.25% of the shares vest on 11/09/2005.  6.25% vest each three months thereafter until all shares are vested on 8/09/2009.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Martin R. Baker</signatureName>
        <signatureDate>2005-08-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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