<SEC-DOCUMENT>0000921895-11-002103.txt : 20111107
<SEC-HEADER>0000921895-11-002103.hdr.sgml : 20111107
<ACCEPTANCE-DATETIME>20111107193141
ACCESSION NUMBER:		0000921895-11-002103
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20111104
FILED AS OF DATE:		20111107
DATE AS OF CHANGE:		20111107

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Armstrong Stevan
		CENTRAL INDEX KEY:			0001533029

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22563
		FILM NUMBER:		111185926

	MAIL ADDRESS:	
		STREET 1:		C/O SG BLOCKS, INC., 400 MADISON AVENUE
		STREET 2:		SUITE 16C
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CDSI HOLDINGS INC
		CENTRAL INDEX KEY:			0001023994
		STANDARD INDUSTRIAL CLASSIFICATION:	BLANK CHECKS [6770]
		IRS NUMBER:				954463937
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		100 S E SECOND STREET
		CITY:			MIAMI
		STATE:			FL
		ZIP:			33131
		BUSINESS PHONE:		3055798000

	MAIL ADDRESS:	
		STREET 1:		100 S E SECOND STREET
		CITY:			MIAMI
		STATE:			FL
		ZIP:			33131

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	PC411 INC
		DATE OF NAME CHANGE:	19961001
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>form308066003b_11072011.xml
<DESCRIPTION>OWNERSHIP DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0204</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2011-11-04</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001023994</issuerCik>
        <issuerName>CDSI HOLDINGS INC</issuerName>
        <issuerTradingSymbol>CDSI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001533029</rptOwnerCik>
            <rptOwnerName>Armstrong Stevan</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SG BLOCKS, INC., 400 MADISON AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 16C</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President, COO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3327266</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By SMA Development Group LLC</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Such shares are held by SMA Development Group, LLC, an entity controlled by Mr. Armstrong. Mr. Armstrong specifically disclaims beneficial ownership of the shares of common stock held by SMA Development Group, LLC, except to the extent of his pecuniary interest therein, and this shall not be deemed to be an admission that Mr. Armstrong is the beneficial owner of such shares of common stock.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Stevan Armstrong</signatureName>
        <signatureDate>2011-11-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
