<SEC-DOCUMENT>0001140361-15-029688.txt : 20150804
<SEC-HEADER>0001140361-15-029688.hdr.sgml : 20150804
<ACCEPTANCE-DATETIME>20150804160317
ACCESSION NUMBER:		0001140361-15-029688
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20150804
FILED AS OF DATE:		20150804
DATE AS OF CHANGE:		20150804

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			HOLOGIC INC
		CENTRAL INDEX KEY:			0000859737
		STANDARD INDUSTRIAL CLASSIFICATION:	X-RAY APPARATUS & TUBES & RELATED IRRADIATION APPARATUS [3844]
		IRS NUMBER:				042902449
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0928

	BUSINESS ADDRESS:	
		STREET 1:		35 CROSBY DRIVE
		CITY:			BEDFORD
		STATE:			MA
		ZIP:			01730
		BUSINESS PHONE:		7819997300

	MAIL ADDRESS:	
		STREET 1:		35 CROSBY DRIVE
		CITY:			BEDFORD
		STATE:			MA
		ZIP:			01730

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ICAHN PARTNERS MASTER FUND LP
		CENTRAL INDEX KEY:			0001322827
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36214
		FILM NUMBER:		151025464

	BUSINESS ADDRESS:	
		STREET 1:		445 HAMILTON AVENUE
		STREET 2:		SUITE 1210
		CITY:			WHITE PLAINS
		STATE:			NY
		ZIP:			10601
		BUSINESS PHONE:		646-861-7060

	MAIL ADDRESS:	
		STREET 1:		445 HAMILTON AVENUE
		STREET 2:		SUITE 1210
		CITY:			WHITE PLAINS
		STATE:			NY
		ZIP:			10601

	FORMER NAME:	
		FORMER CONFORMED NAME:	Icahn Partners Master Fund LP
		DATE OF NAME CHANGE:	20050405

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ICAHN PARTNERS LP
		CENTRAL INDEX KEY:			0001313666
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36214
		FILM NUMBER:		151025465

	BUSINESS ADDRESS:	
		STREET 1:		445 HAMILTON AVENUE
		STREET 2:		SUITE 1210
		CITY:			WHITE PLAINS
		STATE:			NY
		ZIP:			10601
		BUSINESS PHONE:		646-861-7060

	MAIL ADDRESS:	
		STREET 1:		445 HAMILTON AVENUE
		STREET 2:		SUITE 1210
		CITY:			WHITE PLAINS
		STATE:			NY
		ZIP:			10601

	FORMER NAME:	
		FORMER CONFORMED NAME:	Icahn Partners L P
		DATE OF NAME CHANGE:	20050107

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			HIGH RIVER LIMITED PARTNERSHIP
		CENTRAL INDEX KEY:			0000928464

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36214
		FILM NUMBER:		151025466

	BUSINESS ADDRESS:	
		STREET 1:		445 HAMILTON AVENUE
		STREET 2:		SUITE 1210
		CITY:			WHITE PLAINS
		STATE:			NY
		ZIP:			10601
		BUSINESS PHONE:		646-861-7060

	MAIL ADDRESS:	
		STREET 1:		445 HAMILTON AVENUE
		STREET 2:		SUITE 1210
		CITY:			WHITE PLAINS
		STATE:			NY
		ZIP:			10601

	FORMER NAME:	
		FORMER CONFORMED NAME:	HIGH RIVER LIMITED PARTNERSHIP /NY/
		DATE OF NAME CHANGE:	19990517

	FORMER NAME:	
		FORMER CONFORMED NAME:	HIGH RIVER LIMITED PARTNERSHIP
		DATE OF NAME CHANGE:	19950526

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ICAHN CARL C
		CENTRAL INDEX KEY:			0000921669
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36214
		FILM NUMBER:		151025467

	BUSINESS ADDRESS:	
		STREET 1:		C/O ICAHN ASSOCIATES HOLDING LLC
		STREET 2:		767 FIFTH AVE., SUITE 4700
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10153
		BUSINESS PHONE:		212-702-4300

	MAIL ADDRESS:	
		STREET 1:		C/O ICAHN ASSOCIATES HOLDING LLC
		STREET 2:		767 FIFTH AVE., SUITE 4700
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10153

	FORMER NAME:	
		FORMER CONFORMED NAME:	ICAHN CARL C ET AL
		DATE OF NAME CHANGE:	19950612
</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>2015-08-04</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000859737</issuerCik>
        <issuerName>HOLOGIC INC</issuerName>
        <issuerTradingSymbol>HOLX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000921669</rptOwnerCik>
            <rptOwnerName>ICAHN CARL C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ICAHN ASSOCIATES HOLDING LLC</rptOwnerStreet1>
            <rptOwnerStreet2>767 FIFTH AVE., SUITE 4700</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10153</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>no longer subject to Sec. 16</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000928464</rptOwnerCik>
            <rptOwnerName>HIGH RIVER LIMITED PARTNERSHIP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>445 HAMILTON AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1210</rptOwnerStreet2>
            <rptOwnerCity>WHITE PLAINS</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10601</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001313666</rptOwnerCik>
            <rptOwnerName>ICAHN PARTNERS LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>445 HAMILTON AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1210</rptOwnerStreet2>
            <rptOwnerCity>WHITE PLAINS</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10601</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001322827</rptOwnerCik>
            <rptOwnerName>ICAHN PARTNERS MASTER FUND LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>445 HAMILTON AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1210</rptOwnerStreet2>
            <rptOwnerCity>WHITE PLAINS</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10601</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.01 (&quot;Shares&quot;)</value>
            </securityTitle>
            <transactionDate>
                <value>2015-08-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>6000000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>40.47</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>28154879</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>please see all footnotes</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">High River Limited Partnership (&quot;High River&quot;) directly beneficially owns 5,630,974 Shares, Icahn Partners LP (&quot;Icahn Partners&quot;) directly beneficially owns 13,370,741 Shares and Icahn Partners Master Fund LP (&quot;Icahn Master&quot;) directly beneficially owns 9,153,164 Shares.</footnote>
        <footnote id="F2">Barberry Corp. (&quot;Barberry&quot;), is the sole member of Hopper Investments LLC (&quot;Hopper&quot;), which is the general partner of High River. Beckton Corp. (&quot;Beckton&quot;) is the sole stockholder of Icahn Enterprises G.P. Inc. (&quot;Icahn Enterprises GP&quot;), which is the general partner of Icahn Enterprises Holdings L.P. (&quot;Icahn Enterprises Holdings&quot;). Icahn Enterprises Holdings is the sole member of IPH GP LLC (&quot;IPH&quot;), which is the general partner of Icahn Capital LP (&quot;Icahn Capital&quot;). Icahn Capital is the general partner of each of Icahn Onshore LP (&quot;Icahn Onshore&quot;) and Icahn Offshore LP (&quot;Icahn Offshore&quot;). Icahn Onshore is the general partner of Icahn Partners. Icahn Offshore is the general partner of Icahn Master.</footnote>
        <footnote id="F3">Each of Barberry and Beckton is 100% owned by Carl C. Icahn. As such, Mr. Icahn is in a position indirectly to determine the investment and voting decisions made by each of High River, Icahn Partners and Icahn Master. Each of Hopper, Barberry and Mr. Icahn may be deemed to indirectly beneficially own (as that term is defined in Rule 13d-3 under the Act) the Shares which High River owns. Each of Hopper, Barberry and Mr. Icahn disclaims beneficial ownership of such Shares except to the extent of their pecuniary interest therein.</footnote>
        <footnote id="F4">Each of Icahn Onshore, Icahn Capital, IPH, Icahn Enterprises Holdings, Icahn Enterprises GP, Beckton and Mr. Icahn may be deemed to indirectly beneficially own (as that term is defined in Rule 13d-3 under the Act) the Shares which Icahn Partners owns. Each of Icahn Onshore, Icahn Capital, IPH, Icahn Enterprises Holdings, Icahn Enterprises GP, Beckton and Mr. Icahn disclaims beneficial ownership of such Shares except to the extent of their pecuniary interest therein.</footnote>
        <footnote id="F5">Each of Icahn Offshore, Icahn Capital, IPH, Icahn Enterprises Holdings, Icahn Enterprises GP, Beckton and Mr. Icahn may be deemed to indirectly beneficially own (as that term is defined in Rule 13d-3 under the Act) the Shares which Icahn Master owns. Each of Icahn Offshore, Icahn Capital, IPH, Icahn Enterprises Holdings, Icahn Enterprises GP, Beckton and Mr. Icahn disclaims beneficial ownership of such Shares except to the extent of their pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>CARL C. ICAHN</signatureName>
        <signatureDate>2015-08-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>HIGH RIVER LIMITED PARTNERSHIP</signatureName>
        <signatureDate>2015-08-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>ICAHN PARTNERS LP</signatureName>
        <signatureDate>2015-08-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>ICAHN PARTNERS MASTER FUND LP</signatureName>
        <signatureDate>2015-08-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
