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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 4MoM6VztQ8Ld0xL1ewqrBA==

<SEC-DOCUMENT>0001289367-07-000002.txt : 20070312
<SEC-HEADER>0001289367-07-000002.hdr.sgml : 20070312
<ACCEPTANCE-DATETIME>20070312155705
ACCESSION NUMBER:		0001289367-07-000002
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20070312
FILED AS OF DATE:		20070312
DATE AS OF CHANGE:		20070312

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CSP INC /MA/
		CENTRAL INDEX KEY:			0000356037
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMPUTER INTEGRATED SYSTEMS DESIGN [7373]
		IRS NUMBER:				042441294
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			0831

	BUSINESS ADDRESS:	
		STREET 1:		43 MANNING ROAD
		CITY:			BILLERICA
		STATE:			MA
		ZIP:			01821
		BUSINESS PHONE:		9786637598

	MAIL ADDRESS:	
		STREET 1:		43 MANNING ROAD
		CITY:			BILLERICA
		STATE:			MA
		ZIP:			01821

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Lyons J David
		CENTRAL INDEX KEY:			0001289367

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-10843
		FILM NUMBER:		07687649

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		770-664-6823

	MAIL ADDRESS:	
		STREET 1:		3040 COMPTON COURT
		CITY:			ALPHARETTA
		STATE:			MA
		ZIP:			30022
</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>2007-03-12</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000356037</issuerCik>
        <issuerName>CSP INC /MA/</issuerName>
        <issuerTradingSymbol>CSPI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001289367</rptOwnerCik>
            <rptOwnerName>Lyons J David</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3040 COMPTON COURT</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ALPHARETTA</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>30022</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>2007-03-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4842</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>11.272</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Sale of stock</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>J David Lyons</signatureName>
        <signatureDate>2007-03-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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