DexCom Announces Closing of Public Offering of Common Stock

DexCom, Inc. (Nasdaq: DXCM) today announced that it has closed its previously announced public offering of 15,844,000 shares of its common stock at a price of $3.00 per share. In addition, Terrance H. Gregg, DexCom’s President and Chief Executive Officer, also purchased 150,000 additional shares of common stock in this offering at a price per share of $3.12, which represents the last reported bid price on the NASDAQ Global Market of DexCom’s common stock on January 29, 2009. The gross proceeds to DexCom, before expenses, from the sale of the shares were $48 million. Piper Jaffray & Co. acted as sole manager for the offering.

Copies of the prospectus for the offering can be obtained by contacting Piper Jaffray & Co. by mail at 800 Nicollet Mall, Suite 800, Minneapolis, MN 55402 or by telephone at (800) 747-3924.

This press release shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of these securities in any state in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state.

About DexCom, Inc.

DexCom, Inc., headquartered in San Diego, California, is a medical device company focused on the design, development and commercialization of continuous glucose monitoring systems for use by patients at home and by healthcare providers in the hospital.

Cautionary Statement Regarding Forward Looking Statements

DexCom is a medical device company with a limited operating history. Successful commercialization of the company’s products is subject to numerous risks and uncertainties, including a lack of acceptance in the marketplace by physicians and patients, the inability to manufacture products in commercial quantities at an acceptable cost, possible delays in the company’s development programs, the inability of patients to receive reimbursement from third-party payors and inadequate financial and other resources. Certain of these risks and uncertainties, in addition to other risks, are more fully described in the company’s annual report on Form 10-K for the year ended 2007 filed on March 11, 2008, and in the company’s quarterly report on Form 10-Q for the period ending September 30, 2008, as filed with the Securities and Exchange Commission on November 10, 2008.