<SEC-DOCUMENT>0001140361-14-036217.txt : 20140922
<SEC-HEADER>0001140361-14-036217.hdr.sgml : 20140922
<ACCEPTANCE-DATETIME>20140922163720
ACCESSION NUMBER:		0001140361-14-036217
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20140918
FILED AS OF DATE:		20140922
DATE AS OF CHANGE:		20140922

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CODEXIS INC
		CENTRAL INDEX KEY:			0001200375
		STANDARD INDUSTRIAL CLASSIFICATION:	INDUSTRIAL ORGANIC CHEMICALS [2860]
		IRS NUMBER:				710872999
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		200 PENOBSCOT DRIVE
		CITY:			REDWOOD CITY
		STATE:			CA
		ZIP:			94063
		BUSINESS PHONE:		650-421-8100

	MAIL ADDRESS:	
		STREET 1:		200 PENOBSCOT DRIVE
		CITY:			REDWOOD CITY
		STATE:			CA
		ZIP:			94063

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Glaub Kathleen Sereda
		CENTRAL INDEX KEY:			0001619612

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34705
		FILM NUMBER:		141114357

	MAIL ADDRESS:	
		STREET 1:		C/O CODEXIS, INC.
		STREET 2:		200 PENOBSCOT DRIVE
		CITY:			REDWOOD CITY
		STATE:			CA
		ZIP:			94063
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2014-09-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001200375</issuerCik>
        <issuerName>CODEXIS INC</issuerName>
        <issuerTradingSymbol>CDXS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001619612</rptOwnerCik>
            <rptOwnerName>Glaub Kathleen Sereda</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CODEXIS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>200 PENOBSCOT DRIVE</rptOwnerStreet2>
            <rptOwnerCity>REDWOOD CITY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94063</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2014-09-18</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>43478</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>43478</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Restricted Stock. The shares vest as to one third of the shares on each yearly anniversary of September 18, 2014, provided that the Reporting Person provides continuous services to the Issuer as an employee, consultant, director or officer through each such vesting date.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Douglas T. Sheehy, attorney-in-fact for Kathleen Sereda Glaub</signatureName>
        <signatureDate>2014-09-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
