-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 RyVnBtnn0wP4zrYH3zYneWteCwCCkE8cdaCSevKCcdLAgxIDv/b0XqjcmDmO1Ibn
 cQsxck1Wi54UV1J1M7LWag==

<SEC-DOCUMENT>0001351520-06-000001.txt : 20060131
<SEC-HEADER>0001351520-06-000001.hdr.sgml : 20060131
<ACCEPTANCE-DATETIME>20060131213049
ACCESSION NUMBER:		0001351520-06-000001
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20060119
FILED AS OF DATE:		20060131
DATE AS OF CHANGE:		20060131

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Tsang Michael
		CENTRAL INDEX KEY:			0001351520

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-12718
		FILM NUMBER:		06567685

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		408-222-8888

	MAIL ADDRESS:	
		STREET 1:		1235 BORDEAUX DR.
		CITY:			SUNNYVALE
		STATE:			CA
		ZIP:			94089

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SUPERTEX INC
		CENTRAL INDEX KEY:			0000730000
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				942328535
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			0331

	BUSINESS ADDRESS:	
		STREET 1:		1235 BORDEAUX DR
		CITY:			SUNNYVALE
		STATE:			CA
		ZIP:			94089
		BUSINESS PHONE:		4087440100

	MAIL ADDRESS:	
		STREET 1:		1235 BORDEAUX DR
		CITY:			SUNNYVALE
		STATE:			CA
		ZIP:			94089
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2006-01-19</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000730000</issuerCik>
        <issuerName>SUPERTEX INC</issuerName>
        <issuerTradingSymbol>SUPX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001351520</rptOwnerCik>
            <rptOwnerName>Tsang Michael</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1235 BORDEAUX DR.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SUNNYVALE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94089</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>V.P. Standard Products</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>ISO Option (to exercise common stock)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>19.5625</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2005-12-01</value>
            </exerciseDate>
            <expirationDate>
                <value>2007-12-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>ISO Option (to exercise common stock)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>11.3</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2005-09-03</value>
            </exerciseDate>
            <expirationDate>
                <value>2009-09-03</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3500</value>
                    <footnoteId id="F1"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>ISO Option (to exercise common stock)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>17.34</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2005-12-01</value>
            </exerciseDate>
            <expirationDate>
                <value>2010-12-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5000</value>
                    <footnoteId id="F2"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>ISO Option (to exercise common stock)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>15.67</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2005-06-01</value>
            </exerciseDate>
            <expirationDate>
                <value>2011-06-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5000</value>
                    <footnoteId id="F3"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>ISO Option (to exercise common stock)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>17.39</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2006-06-01</value>
            </exerciseDate>
            <expirationDate>
                <value>2012-06-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5000</value>
                    <footnoteId id="F4"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">500 shares currently exercisable as of 9/3/2005.  1,500 shares exercisable on 9/3/2006. 1,500 shares exercisable on 9/3/2007.</footnote>
        <footnote id="F2">2,000 shares currently exercisable as of 12/1/2005.  1,000 shares exercisable on 12/1/2006.  1,000 shares exercisable on 12/1/2007.  1,000 shares exercisable on 12/1/2008.</footnote>
        <footnote id="F3">1,000 shares currently exercisable as of 6/1/2005.  1,000 shares exercisable on 6/1/2006.  1,000 shares exercisable on 6/1/2007.  1,000 shares exercisable on 6/1/2008.  1,000 shares exercisable on 6/1/2009.</footnote>
        <footnote id="F4">1,000 shares exercisable on 06/01/2006. 1,000 shares exercisable on 06/01/2007. 1,000 shares exercisable on 06/01/2008. 1,000 shares exercisable on 06/01/2009. 1,000 shares exercisable on 06/01/2010.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Michael Tsang</signatureName>
        <signatureDate>2006-01-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----