-----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,
 LdgSZn/LSbbbz+sfxT7JU+VrPR26JTSAYEFO+8DPoS7L9BJBDvwJDE0krIjGggfA
 hH9OgEYgB1wL9eXQyO4NnQ==

<SEC-DOCUMENT>0001179110-09-011586.txt : 20090804
<SEC-HEADER>0001179110-09-011586.hdr.sgml : 20090804
<ACCEPTANCE-DATETIME>20090804191636
ACCESSION NUMBER:		0001179110-09-011586
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090731
FILED AS OF DATE:		20090804
DATE AS OF CHANGE:		20090804

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			WENTZ DAVE
		CENTRAL INDEX KEY:			0001203343

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-21116
		FILM NUMBER:		09985271

	MAIL ADDRESS:	
		STREET 1:		308 W 300
		STREET 2:		S #203
		CITY:			SALT LAKE CITY
		STATE:			UT
		ZIP:			84101

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			USANA HEALTH SCIENCES INC
		CENTRAL INDEX KEY:			0000896264
		STANDARD INDUSTRIAL CLASSIFICATION:	MEDICINAL CHEMICALS & BOTANICAL PRODUCTS [2833]
		IRS NUMBER:				870500306
		STATE OF INCORPORATION:			UT
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		3838 WEST PARKWAY BLVD.
		CITY:			SALT LAKE CITY
		STATE:			UT
		ZIP:			84120-6336
		BUSINESS PHONE:		8019547100

	MAIL ADDRESS:	
		STREET 1:		3838 WEST PARKWAY BLVD.
		STREET 2:		3838 WEST PARKWAY BLVD.
		CITY:			SALT LAKE CITY
		STATE:			UT
		ZIP:			84120-6336

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	USANA INC
		DATE OF NAME CHANGE:	19930125
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-07-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000896264</issuerCik>
        <issuerName>USANA HEALTH SCIENCES INC</issuerName>
        <issuerTradingSymbol>USNA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001203343</rptOwnerCik>
            <rptOwnerName>WENTZ DAVE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3838 WEST PARKWAY BLVD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SALT LAKE CITY</rptOwnerCity>
            <rptOwnerState>UT</rptOwnerState>
            <rptOwnerZipCode>84120</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>C.E.O.</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-07-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>35.37</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>256209</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-08-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.6</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>251209</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>James Bramble as attorney in fact</signatureName>
        <signatureDate>2009-08-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----