In Celebration of the 31st Annual Dialysis Conference, NxStage(R) Announces Over 5,000 Patients Using the System One(TM) for Home Hemodialysis

Thursday February 17, 2011

LAWRENCE, Mass., Feb. 17, 2011 /PRNewswire via COMTEX/ —

In celebration of the 31st Annual Dialysis Conference, NxStage&reg Medical, Inc. (Nasdaq: NXTM), a leading manufacturer of innovative dialysis products, today announced that more than 5,000 patients are using the NxStage System One for home hemodialysis. The System One is the only portable home hemodialysis machine cleared for home use by the FDA.

This new milestone demonstrates growing support of home and more frequent hemodialysis with the System One from patients and providers within the renal community, said Jeff Burbank, Founder and CEO of NxStage Medical, Inc. Many of these patients and providers have become enthusiastic advocates of our therapy and should be credited with growing patient access to the clinical and quality of life benefits possible with more frequent hemodialysis with the System One.

The NxStage&reg System One&#153 has been used in approximately four million treatments since its FDA clearance as the first truly portable home hemodialysis system. Unlike traditional dialysis equipment, the System One plugs into a standard electrical outlet and requires no special infrastructure for operation. Trained patients accompanied by their trained partners work the easy-to-use device. Rather than commuting to and from a dialysis clinic three times per week for scheduled treatment sessions lasting three to four hours, NxStage patients have the personal freedom to conduct prescribed treatments at home on their own schedule or to bring the System One with them while traveling. The System One works in concert with NxStage’s PureFlow&#153 SL dialysate preparation system, a compact, easy-to-use system that prepares high-purity dialysate from regular tap water, helping to make daily home hemodialysis even more practical and accessible to patients. The PureFlow SL eliminates the need for bagged dialysate in the home, while still allowing patients to use bagged fluids when they travel.

The 31st Annual Dialysis Conference is being held in Phoenix, AZ from February 20-22nd, with pre-conference symposiums – including a course dedicated to home hemodialysis – on February 19th. The Annual Dialysis Conference attracts thousands of healthcare practitioners to discuss current developments in dialysis. NxStage will be celebrating the 5,000 patient milestone at an invitation-only educational event for attendees of the conference on Monday, February 21st. The event, entitled Leading a Renal Revolution, Together, will feature a kidney patient sharing his experiences, a leading home hemodialysis nephrologist discussing the need for a paradigm shift in ESRD care, and NxStage’s perspective on growth to date in home hemodialysis.

About NxStage Medical

NxStage Medical, Inc. (Nasdaq: NXTM) is a medical device company, headquartered in Lawrence, Massachusetts, USA, that develops, manufactures and markets innovative systems for the treatment of end-stage renal disease, or ESRD, and acute kidney failure. NxStage is leading the development of the home hemodialysis market in the US with the only portable hemodialysis machine, the System One, cleared for home use by the FDA. For more information on NxStage and its products, please visit the company’s website at http://www.nxstage.com/.

Forward-Looking Statements

This release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this release that are not clearly historical in nature are forward-looking, and the words anticipate, believe, expect, estimate, plan, and similar expressions are generally intended to identify forward-looking statements. All forward-looking statements involve risks, uncertainties and contingencies, many of which are beyond NxStage’s control, which may cause actual results, performance, or achievements to differ materially from anticipated results, performance or achievements including those factors that may affect future operating results and which are detailed in NxStage’s filings with the Securities and Exchange Commission, including Quarterly Report on Form 10Q for the quarter ended September 30, 2010.

In addition, the statements in this press release represent NxStage’s expectations and beliefs as of the date of this press release. NxStage anticipates that subsequent events and developments may cause these expectations and beliefs to change. However, while NxStage may elect to update these forward-looking statements at some point in the future, it specifically disclaims any obligation to do so, whether as a result of new information, future events, or otherwise. These forward-looking statements should not be relied upon as representing NxStage’s expectations or beliefs as of any date subsequent to the date of this press release.

Investor Relations Contact

Kristen Sheppard

NxStage Medical, Inc.

ir@nxstage.com

978-332-5923

SOURCE NxStage Medical, Inc.