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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 S8mMZcub+wkyQ/WQPMDf3G3iENsHgm1knzKdV3/wtYlzMP2JLouwuez+VpJIpd++
 +9+FwS59ugCtfPL6u8UpaQ==

<SEC-DOCUMENT>0001258119-08-000001.txt : 20080118
<SEC-HEADER>0001258119-08-000001.hdr.sgml : 20080118
<ACCEPTANCE-DATETIME>20080118213752
ACCESSION NUMBER:		0001258119-08-000001
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080118
FILED AS OF DATE:		20080118
DATE AS OF CHANGE:		20080118

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MoSys, Inc.
		CENTRAL INDEX KEY:			0000890394
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				770291941
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		755 N MATIHILDA AVENUE
		CITY:			SUNNYVALE
		STATE:			CA
		ZIP:			94085
		BUSINESS PHONE:		408 731 1800

	MAIL ADDRESS:	
		STREET 1:		755 N MATIHILDA AVENUE
		CITY:			SUNNYVALE
		STATE:			CA
		ZIP:			94085

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MONOLITHIC SYSTEM TECHNOLOGY INC
		DATE OF NAME CHANGE:	19960613

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SULLIVAN JAMES
		CENTRAL INDEX KEY:			0001254117

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-32929
		FILM NUMBER:		08540003

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		408 727 1885

	MAIL ADDRESS:	
		STREET 1:		3151 JAY STREET
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95054
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2008-01-18</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000890394</issuerCik>
        <issuerName>MoSys, Inc.</issuerName>
        <issuerTradingSymbol>mosy</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001254117</rptOwnerCik>
            <rptOwnerName>SULLIVAN JAMES</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>755 N. MATHILDA AVE. SUITE 100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SUNNYVALE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94085</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP of Finance and CFO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <ownerSignature>
        <signatureName>James W. Sullivan</signatureName>
        <signatureDate>2008-01-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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