-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 I3J1i/p3Vxr9MWtb1lQXNFJcQb++4Cvn09DcOB5eTqlN8hAScJ0VsKdHzeqC/IbX
 N0YwUDrLO7UbHhJALt9EMw==

<SEC-DOCUMENT>0001104659-07-087509.txt : 20071206
<SEC-HEADER>0001104659-07-087509.hdr.sgml : 20071206
<ACCEPTANCE-DATETIME>20071206180018
ACCESSION NUMBER:		0001104659-07-087509
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20071205
FILED AS OF DATE:		20071206
DATE AS OF CHANGE:		20071206

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			AMAG PHARMACEUTICALS INC.
		CENTRAL INDEX KEY:			0000792977
		STANDARD INDUSTRIAL CLASSIFICATION:	IN VITRO & IN VIVO DIAGNOSTIC SUBSTANCES [2835]
		IRS NUMBER:				042742593
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		125 CAMBRIDGEPARK DRIVE, 6TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02140
		BUSINESS PHONE:		6174972070

	MAIL ADDRESS:	
		STREET 1:		125 CAMBRIDGEPARK DRIVE, 6TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02140

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ADVANCED MAGNETICS INC
		DATE OF NAME CHANGE:	19920703

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Healey Timothy G
		CENTRAL INDEX KEY:			0001382032

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-14732
		FILM NUMBER:		071290536

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		617-498-3300

	MAIL ADDRESS:	
		STREET 1:		C/O ADVANCED MAGNETICS, INC.
		STREET 2:		125 CAMBRIDGEPARK DRIVE, 6TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02140
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>a4.xml
<DESCRIPTION>4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-12-05</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000792977</issuerCik>
        <issuerName>AMAG PHARMACEUTICALS INC.</issuerName>
        <issuerTradingSymbol>AMAG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001382032</rptOwnerCik>
            <rptOwnerName>Healey Timothy G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AMAG PHARMACEUTICALS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>125 CAMBRIDGE PARK DRIVE</rptOwnerStreet2>
            <rptOwnerCity>CAMBRIDGE</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02140</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP - Commercial Operations</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-12-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>750</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>59.12</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>270</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>/s/ Joseph L. Farmer, attorney-in-fact</signatureName>
        <signatureDate>2007-12-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----