-----BEGIN PRIVACY-ENHANCED MESSAGE-----
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,
 TpZOiV8HEfN7O5y7ZyWVO6D4MaTEBhcMkS8z53bxnF+uMos/ZVXa09n4FZgcxeaE
 G3g2RlRmqqoX1yT+ZDyVrA==

<SEC-DOCUMENT>0001253532-03-000004.txt : 20030804
<SEC-HEADER>0001253532-03-000004.hdr.sgml : 20030804
<ACCEPTANCE-DATETIME>20030804104305
ACCESSION NUMBER:		0001253532-03-000004
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20010410
FILED AS OF DATE:		20030804

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CUNO INC
		CENTRAL INDEX KEY:			0001019779
		STANDARD INDUSTRIAL CLASSIFICATION:	GENERAL INDUSTRIAL MACHINERY & EQUIPMENT, NEC [3569]
		IRS NUMBER:				061159240
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1031

	BUSINESS ADDRESS:	
		STREET 1:		400 RESEARCH PARKWAY
		CITY:			MERIDEN
		STATE:			CT
		ZIP:			06450
		BUSINESS PHONE:		2032375541

	MAIL ADDRESS:	
		STREET 1:		400 RESEARCH PARKWAY
		CITY:			MERIDEN
		STATE:			CT
		ZIP:			06450

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CARNEY TIMOTHY B
		CENTRAL INDEX KEY:			0001253528

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-21109
		FILM NUMBER:		03819402

	BUSINESS ADDRESS:	
		STREET 1:		400 RESEARCH PARKWAY
		CITY:			MERIDEN
		STATE:			CT
		ZIP:			06450
		BUSINESS PHONE:		2032388749

	MAIL ADDRESS:	
		STREET 1:		400 RESEARCH PARKWAY
		CITY:			MERIDEN
		STATE:			CT
		ZIP:			06450
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2001-04-10</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001019779</issuerCik>
        <issuerName>CUNO INC</issuerName>
        <issuerTradingSymbol>CUNO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001253528</rptOwnerCik>
            <rptOwnerName>CARNEY TIMOTHY B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>400 RESEARCH PARKWAY</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MERIDEN</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06450</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>

        <nonDerivativeTransaction>
            <securityTitle>
                <value>Restricted Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2003-07-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>36.3</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14655</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

    </nonDerivativeTable>



    <ownerSignature>
        <signatureName>Timothy B. Carney</signatureName>
        <signatureDate>2003-08-04</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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