Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
ROBERTS BRYAN E
   2. Issuer Name and Ticker or Trading Symbol
IRONWOOD PHARMACEUTICALS INC [IRWD] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
C/O VENROCK, 3340 HILLVIEW AVENUE		 3. Date of Earliest Transaction (Month/Day/Year)
03/03/2015
(Street)

PALO ALTO, CA 94304		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Class A Common Stock 03/03/2015   J(1)   16,498 D $ 0 0 I By Funds (2)
Class A Common Stock 03/03/2015   J(3)   1,919,704 D $ 0 0 I By Funds (4)
Class A Common Stock 03/03/2015   J(5)   148 A $ 0 253 I By LLC (6)
Class A Common Stock 03/03/2015   J(7)   64 A $ 0 15,085 (8) D  
Class A Common Stock               33,117 I By LLC (8) (9)
Class A Common Stock               88,262 I By Funds (10)
Class A Common Stock               7,483 I By Funds (11)
Class A Common Stock               18,910 I By Funds (12)
Class B Common Stock               40,000 I By LLC (13)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
ROBERTS BRYAN E
C/O VENROCK
3340 HILLVIEW AVENUE
PALO ALTO, CA 94304		   X      

Signatures

 /s/ Bryan E. Roberts   03/05/2015
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) On March 3, 2015, Venrock Entrepreneurs Fund, L.P. ("VEF") distributed an aggregate of 16,498 shares of the Class A Common Stock of the Issuer to its partners pro rata based on their respective interests in VEF. After the distribution, VEF held an aggregate of 0 shares of Class A Common Stock of the Issuer.
(2) VEF holds an aggregate of 0 shares of Class A Common Stock of the Issuer. Venrock Management, LLC ("VM") is the sole general partner of VEF and may be deemed to beneficially own these shares. Dr. Roberts is a member of VM and may be deemed to beneficially own these shares. Dr. Roberts and VM expressly disclaim beneficial ownership over all shares held by VEF, except to the extent of their indirect pecuniary interests therein.
(3) On March 3, 2015, Venrock Associates ("VA") distributed an aggregate of 1,919,704 shares of the Class A Common Stock of the Issuer to its partners pro rata based on their respective interests in VA. After the distribution, VA held an aggregate of 0 shares of Class A Common Stock of the Issuer.
(4) VA holds an aggregate of 0 shares of Class A Common Stock of the Issuer. The reporting person is a general partner of VA and may be deemed to beneficially own these shares. The reporting person disclaims beneficial ownership of these shares except to the extent of his indirect pecuniary interest therein.
(5) In the distribution, VM received an aggregate of 148 shares. For VM, this represents a change in form of ownership from indirect to direct but does not represent a change in beneficial ownership.
(6) VM holds an aggregate of 253 shares of Class A Common Stock of the Issuer. Dr. Roberts is a member of VM and may be deemed to beneficially own these shares. Dr. Roberts expressly disclaims beneficial ownership over all shares held by VM, except to the extent of his indirect pecuniary interest therein.
(7) In the distribution, Dr. Roberts received an aggregate of 64 shares in connection with his partnership interest in VA. For Dr. Roberts, this represents a change in form of ownership from indirect to direct but does not represent a change in beneficial ownership.
(8) In September 2014 and January 2015, Dr. Roberts transferred an aggregate of 198 shares of the Class A Common Stock of the Issuer and 182 shares of the Class A Common Stock of the Issuer, respectively, to VR Management, LLC (the "Management Company"). For Dr. Roberts, this represents a change in form of ownership from direct to indirect but does not represent a change in beneficial ownership.
(9) Consists of 33,117 shares of Class A Common Stock of the issuer held by the Management Company. Dr. Roberts is a member of the Management Company and may be deemed to beneficially own these shares. Dr. Roberts disclaims beneficial ownership of these shares except to the extent of his indirect pecuniary interest therein.
(10) Venrock Associates V, L.P. ("VA5") holds an aggregate of 88,262 shares of Class A Common Stock of the Issuer. Venrock Management V, LLC ("VM5") is the sole general partner of VA5 and may be deemed to beneficially own these shares. Dr. Roberts is a member of VM5 and may be deemed to beneficially own these shares. Dr. Roberts and VM5 expressly disclaim beneficial ownership over all shares held by VA5, except to the extent of their indirect pecuniary interests therein.
(11) Venrock Partners V, L.P. ("VP5") holds an aggregate of 7,483 shares of Class A Common Stock of the Issuer. Venrock Partners Management V, LLC ("VPM5") is the sole general partner of VP5 and may be deemed to beneficially own these shares. Dr. Roberts is a member of VPM5 and may be deemed to beneficially own these shares. Dr. Roberts and VPM5 expressly disclaim beneficial ownership over all shares held by VP5, except to the extent of their indirect pecuniary interests therein.
(12) VHCP Management, LLC ("VHCP Management") holds an aggregate of 18,910 shares of Class A Common Stock of the Issuer. Dr. Roberts is a managing member of VHCP Management and may be deemed to beneficially own these shares. Dr. Roberts expressly disclaims beneficial ownership over these shares except to the extent of his indirect pecuniary interest therein.
(13) Consists of 40,000 shares of Class B Common Stock of the issuer held by the Managment Company. Dr. Roberts is a member of the Management Company and may be deemed to beneficially own these shares. Dr. Roberts disclaims beneficial ownership of these shares except to the extent of his indirect pecuniary interest therein.

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