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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,
 Q/I3TiWxMYIhT40rpXna0fUP5KkVrHBmuqn+X7eRJY37L857vA0VsftE5chroUEY
 8oPFDKOuoSA3sKcNWs0r+w==

<SEC-DOCUMENT>0001029296-04-000010.txt : 20040524
<SEC-HEADER>0001029296-04-000010.hdr.sgml : 20040524
<ACCEPTANCE-DATETIME>20040524120832
ACCESSION NUMBER:		0001029296-04-000010
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040521
FILED AS OF DATE:		20040524

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BISCO INDUSTRIES INC
		CENTRAL INDEX KEY:			0001029296
		STATE OF INCORPORATION:			IL

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-10394
		FILM NUMBER:		04826057

	BUSINESS ADDRESS:	
		STREET 1:		1500 N. LAKEVIEW AVE.
		CITY:			ANAHEIM
		STATE:			CA
		ZIP:			92807
		BUSINESS PHONE:		7146932901

	MAIL ADDRESS:	
		STREET 1:		1500 N. LAKEVIEW AVE.
		CITY:			ANAHEIM
		STATE:			CA
		ZIP:			92807

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			DATA I/O CORP
		CENTRAL INDEX KEY:			0000351998
		STANDARD INDUSTRIAL CLASSIFICATION:	INSTRUMENTS FOR MEAS & TESTING OF ELECTRICITY & ELEC SIGNALS [3825]
		IRS NUMBER:				910864123
		STATE OF INCORPORATION:			WA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		10525 WILLOWS RD NE
		STREET 2:		P O BOX 97046
		CITY:			REDMOND
		STATE:			WA
		ZIP:			98073-9746
		BUSINESS PHONE:		4258676922

	MAIL ADDRESS:	
		STREET 1:		P O BOX 97046
		STREET 2:		10525 WILLOWS RD NE
		CITY:			REDMOND
		STATE:			WA
		ZIP:			98073-9746
</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>2004-05-21</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000351998</issuerCik>
        <issuerName>DATA I/O CORP</issuerName>
        <issuerTradingSymbol>DAIO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001029296</rptOwnerCik>
            <rptOwnerName>BISCO INDUSTRIES INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1500 N. LAKEVIEW AVE.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ANAHEIM</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92807</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Data I/O</value>
            </securityTitle>
            <transactionDate>
                <value>2004-05-21</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>200</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>2.85</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>851473</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Bisco Industries, Inc.</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>Glen Ceiley</signatureName>
        <signatureDate>2004-05-24</signatureDate>
    </ownerSignature>
</ownershipDocument>

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