<SEC-DOCUMENT>0001127602-14-034702.txt : 20141210
<SEC-HEADER>0001127602-14-034702.hdr.sgml : 20141210
<ACCEPTANCE-DATETIME>20141210161559
ACCESSION NUMBER:		0001127602-14-034702
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20141208
FILED AS OF DATE:		20141210
DATE AS OF CHANGE:		20141210

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:			MERKSAMER SAMUEL J.
		CENTRAL INDEX KEY:			0001501581

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36214
		FILM NUMBER:		141278163

	MAIL ADDRESS:	
		STREET 1:		C/O ICAHN CAPITAL LP
		STREET 2:		767 FIFTH AVENUE, 47TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10153

	FORMER NAME:	
		FORMER CONFORMED NAME:	MERKSAMER SAMUEL
		DATE OF NAME CHANGE:	20100920

	FORMER NAME:	
		FORMER CONFORMED NAME:	MERKSAMER SAM
		DATE OF NAME CHANGE:	20100917
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form4.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2014-12-08</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001501581</rptOwnerCik>
            <rptOwnerName>MERKSAMER SAMUEL J.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>35 CROSBY DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BEDFORD</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01730</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2014-12-08</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2590</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>26.63</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2590</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Unit Award (Right To Receive)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2014-12-08</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2590</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2017-12-08</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2590</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5261</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">These shares represent restricted stock units (RSUs) awarded to the Reporting Person pursuant to the 2008 Equity Incentive Plan and are subject to vesting as provided in the agreement evidencing the award.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Mark J. Casey, Attorney-In-Fact for Mr. Samuel J. Merksamer</signatureName>
        <signatureDate>2014-12-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
