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 * Gilbert Halley E   2. Issuer Name and Ticker or Trading Symbol IRONWOOD PHARMACEUTICALS INC [IRWD] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Chief Legal Officer (Last) (First) (Middle) C/O IRONWOOD PHARMACEUTICALS, INC., 301 BINNEY STREET 3. Date of Earliest Transaction (Month/Day/Year) 02/14/2017 (Street) CAMBRIDGE, MA 02142 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 B Common Stock 02/14/2017   M   37,385 A $ 3.76 37,385 D   Class B Common Stock 02/14/2017   S(1)   37,385 D $ 16.75 0 D   Class A Common Stock               65,846 (2) D

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

Employee Stock Option (Right to Buy)

$ 3.76

02/14/2017

M

37,385

(3)

01/31/2018

Class B Common Stock

37,385

$ 3.76

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Gilbert Halley E C/O IRONWOOD PHARMACEUTICALS, INC. 301 BINNEY STREET CAMBRIDGE, MA 02142			Chief Legal Officer

Signatures

/s/ Conor Kilroy, Attorney-in-Fact		02/15/2017
**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)	This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person. In order to effect the sale, these shares of Class B Common Stock were converted into shares of Class A Common Stock in accordance with the issuer's certificate of incorporation.
(2)	The reporting person acquired 379 shares of Class A Common Stock under the issuer's employee stock purchase plan on December 31, 2016.
(3)	The option vested as to 25% of the shares of Class B Common Stock on the first anniversary of February 1, 2008, and 1/48th of the shares of Class B Common Stock vested each month thereafter for the next 36 months. The option was fully vested as of February 1, 2012.
Remarks: Exhibit 24: Power of Attorney

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