-----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,
 Rh5xSk377yTG8PZHxWvVRwR74TtagPa5JeG3ZGjV7FjPHdx5wFBwQxcArAPEydu1
 duhXcmhSYbvRIstjTjHEQw==

<SEC-DOCUMENT>0000315066-10-003521.txt : 20101104
<SEC-HEADER>0000315066-10-003521.hdr.sgml : 20101104
<ACCEPTANCE-DATETIME>20101104114147
ACCESSION NUMBER:		0000315066-10-003521
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100802
FILED AS OF DATE:		20101104
DATE AS OF CHANGE:		20101104

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			IRONWOOD PHARMACEUTICALS INC
		CENTRAL INDEX KEY:			0001446847
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				043404176

	BUSINESS ADDRESS:	
		STREET 1:		301 BINNEY STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142
		BUSINESS PHONE:		617-621-7722

	MAIL ADDRESS:	
		STREET 1:		301 BINNEY STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FMR LLC
		CENTRAL INDEX KEY:			0000315066
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34620
		FILM NUMBER:		101163780

	BUSINESS ADDRESS:	
		STREET 1:		82 DEVONSHIRE ST
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02109
		BUSINESS PHONE:		6175706339

	MAIL ADDRESS:	
		STREET 1:		82 DEVONSHIRE STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02109

	FORMER NAME:	
		FORMER CONFORMED NAME:	FMR CORP
		DATE OF NAME CHANGE:	19920717
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-08-02</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001446847</issuerCik>
        <issuerName>IRONWOOD PHARMACEUTICALS INC</issuerName>
        <issuerTradingSymbol>IRWD</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000315066</rptOwnerCik>
            <rptOwnerName>FMR LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>82 DEVONSHIRE STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Edward C. Johnson 3d</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <remarks>FMR LLC is no longer subject to Section 16 based on updated information on Class A Common Stock outstanding provided by the issuer to the NASDAQ Stock Market on October 5, 2010.</remarks>

    <ownerSignature>
        <signatureName>Scott C. Goebel, Duly authorized under Powers of Attorney effective as of June 1, 2008, by and on behalf of FMR LLC and its direct and indirect subsidiaries, and by and on behalf of Edward C. Johnson 3d</signatureName>
        <signatureDate>2010-11-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----