Ironwood Pharmaceuticals Prices Public Offering Of Common Stock

Ironwood Pharmaceuticals, Inc. (NASDAQ: IRWD) (the “Company”) announced today the pricing of an underwritten public offering of 5,250,000 shares of its Class A common stock at a price of $15.09 per share to the public. All of the shares are being offered by Ironwood. The gross proceeds to Ironwood from this offering are expected to be approximately $79.2 million, before deducting underwriting discounts and commissions, and other estimated offering expenses payable by Ironwood. The offering is expected to close on February 15, 2012, subject to the satisfaction of customary closing conditions.

The Company intends to use the net proceeds from this offering for general corporate purposes, including to further strengthen its balance sheet in advance of the potential market launch of linaclotide (if approved).

J.P. Morgan Securities LLC and BofA Merrill Lynch are acting as joint active bookrunning managers and Morgan Stanley & Co. LLC is acting as passive bookrunning manager of the offering. Ladenburg Thalmann & Co., Inc. is acting as a co-manager of the offering. Ironwood has granted the underwriters a 30-day option to purchase up to an additional 15 percent of the amount of shares sold.

A preliminary prospectus supplement related to the offering has been filed with the SEC and will be available on the SEC's website located at www.sec.gov. Copies of the preliminary prospectus supplement and the accompanying prospectus relating to this offering may be obtained from the offices of: J.P. Morgan Securities LLC, c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, New York 11717 (telephone number: 866-803-9204) or from BofA Merrill Lynch, 4 World Financial Center, New York, New York 10080, Attention: Prospectus Department or by emailing [e-mail].

The securities described above are being offered by Ironwood pursuant to an automatically effective shelf registration statement that was previously filed with the SEC. This press release shall not constitute an offer to sell, or the solicitation of an offer to buy, any of the securities, nor shall there be any sale of these securities, in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.