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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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<SEC-DOCUMENT>0000350557-07-000064.txt : 20071217
<SEC-HEADER>0000350557-07-000064.hdr.sgml : 20071217
<ACCEPTANCE-DATETIME>20071217144012
ACCESSION NUMBER:		0000350557-07-000064
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20071213
FILED AS OF DATE:		20071217
DATE AS OF CHANGE:		20071217

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

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:		071309778

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		612-746-1915

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

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>2.5</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-12-13</value>
                <footnoteId id="F1"/>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5000</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>5000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This Form 4 reports an option granted in connection with the reporting person's appointment as a director of the issuer. The option previously reported as granted on August 10, 2007 was not effectively granted.  Therefore, the two options granted on December 13, 2007 (one of which was previously reported and one of which is reported on this Form 4) are the only options held by the reporting person as of the date of this Form 4 filing.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Steven F. Sabes, by Power of Attorney</signatureName>
        <signatureDate>2007-12-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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