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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 PUuU3jsLPxvIFvSv880ZKlLPuZagcyrk6I0FsFC3NiAOpJaodcgVVXADigSlfYZv
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<SEC-DOCUMENT>0001140361-09-004572.txt : 20090218
<SEC-HEADER>0001140361-09-004572.hdr.sgml : 20090218
<ACCEPTANCE-DATETIME>20090218212018
ACCESSION NUMBER:		0001140361-09-004572
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090216
FILED AS OF DATE:		20090218
DATE AS OF CHANGE:		20090218

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			U.S. Auto Parts Network, Inc.
		CENTRAL INDEX KEY:			0001378950
		STANDARD INDUSTRIAL CLASSIFICATION:	RETAIL-AUTO & HOME SUPPLY STORES [5531]
		IRS NUMBER:				680623433
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		17150 SOUTH MARGAY AVENUE
		CITY:			CARSON
		STATE:			CA
		ZIP:			90746
		BUSINESS PHONE:		(310) 715-6666

	MAIL ADDRESS:	
		STREET 1:		17150 SOUTH MARGAY AVENUE
		CITY:			CARSON
		STATE:			CA
		ZIP:			90746

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SANDERS THEODORE R
		CENTRAL INDEX KEY:			0001244638

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33264
		FILM NUMBER:		09620014

	BUSINESS ADDRESS:	
		STREET 1:		2555 WEST 190TH STREET
		CITY:			TORRANCE
		STATE:			CA
		ZIP:			90504
		BUSINESS PHONE:		909-444-8888

	MAIL ADDRESS:	
		STREET 1:		C/O VIEWSONIC CORPORATION
		STREET 2:		381 BREA CANYON ROAD
		CITY:			WALNUT
		STATE:			CA
		ZIP:			91789
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-02-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001378950</issuerCik>
        <issuerName>U.S. Auto Parts Network, Inc.</issuerName>
        <issuerTradingSymbol>PRTS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001244638</rptOwnerCik>
            <rptOwnerName>SANDERS THEODORE R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O U.S. AUTO PARTS NETWORK, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>17150 MARGAY AVENUE</rptOwnerStreet2>
            <rptOwnerCity>CARSON</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90746</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Financial Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Option (right To buy)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.15</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-02-16</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>400000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2010-02-16</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2019-02-15</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>400000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>400000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Option (right To buy)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.15</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-02-16</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>100000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2019-02-15</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>100000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>500000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Granted pursuant to the U.S. Auto Parts Network, Inc. New Employee Incentive Plan.</footnote>
        <footnote id="F2">Twenty-five percent (25%) of the option shares vest and become exercisable upon the first anniversary of the date of grant, and thereafter the balance of the option shares vest and become exercisable in a series of thirty-six equal monthly installments over the three year period measured from the one year anniversary of the date of grant. All option shares shall vest on an accelerated basis and become immediately exercisable upon the involuntary termination of Mr. Sander's employment with U.S. Auto Parts Network, Inc. (the &quot;Company&quot;) within twelve (12) months following certain changes in control of the Company.</footnote>
        <footnote id="F3">The option shares shall become vested Shares on the last day of any consecutive three calendar months when and if the average of the Monthly Average Prices of the Common Stock during such three month period reaches or exceeds $5.00.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Theodore R. Sanders</signatureName>
        <signatureDate>2009-02-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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