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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,
 E0qcwGG/Z9UWVa+RUp8Elc1bpmyQMZD6qwi0N+/RhJW3nPSk7+k/MQFnaDw6e7yL
 T0sTQzDcBXm6lzPa2MWuxQ==

<SEC-DOCUMENT>0000350557-07-000063.txt : 20071213
<SEC-HEADER>0000350557-07-000063.hdr.sgml : 20071213
<ACCEPTANCE-DATETIME>20071213155801
ACCESSION NUMBER:		0000350557-07-000063
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20071213
FILED AS OF DATE:		20071213
DATE AS OF CHANGE:		20071213

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SABES STEVEN F
		CENTRAL INDEX KEY:			0001406756

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-18785
		FILM NUMBER:		071304652

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		612-746-1915

	MAIL ADDRESS:	
		STREET 1:		60 SOUTH SIXTH STREET, SUITE 950
		CITY:			MINNEAPOLIS
		STATE:			MN
		ZIP:			55402

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			STEN CORP
		CENTRAL INDEX KEY:			0000350557
		STANDARD INDUSTRIAL CLASSIFICATION:	SHORT-TERM BUSINESS CREDIT INSTITUTIONS [6153]
		IRS NUMBER:				411391803
		STATE OF INCORPORATION:			MN
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		10275 WAYZATA BLVD.
		STREET 2:		SUITE 310
		CITY:			MINNETONKA
		STATE:			MN
		ZIP:			55305
		BUSINESS PHONE:		952-545-2776

	MAIL ADDRESS:	
		STREET 1:		10275 WAYZATA BLVD.
		STREET 2:		SUITE 310
		CITY:			MINNETONKA
		STATE:			MN
		ZIP:			55305

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	STERION INC
		DATE OF NAME CHANGE:	20020212

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	OXBORO MEDICAL INC
		DATE OF NAME CHANGE:	20000322

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	OXBORO MEDICAL INTERNATIONAL INC
		DATE OF NAME CHANGE:	19920703
</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>2007-12-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000350557</issuerCik>
        <issuerName>STEN CORP</issuerName>
        <issuerTradingSymbol>sten</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001406756</rptOwnerCik>
            <rptOwnerName>SABES STEVEN F</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>60 SOUTH SIXTH STREET, SUITE 950</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MINNEAPOLIS</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55402</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>2.5</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-12-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2007-12-13</value>
            </exerciseDate>
            <expirationDate>
                <value>2012-12-13</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <ownerSignature>
        <signatureName>Steven F. Sabes, By Power of Attorney</signatureName>
        <signatureDate>2007-12-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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