(d) On November 9, 2012, Jean K. Mixer accepted her appointment to the Board of Directors of NxStage Medical, Inc. The appointment of Ms. Mixer to the Board increases the total number of directors on the Board to ten. Ms. Mixer will serve as a director until NxStage's 2013 annual meeting of stockholders. Ms. Mixer was not appointed to any committees of NxStage's Board of Directors.

Ms. Mixer will be entitled to receive compensation for her service on the Board of Directors consistent with NxStage's director compensation program for non-employee directors, as described under the heading Director Compensation in NxStage's proxy statement for its 2012 Annual Meeting of Stockholders as filed with the Securities and Exchange Commission on April 24, 2012, which description is incorporated in this Form 8-K by reference.

In connection with Ms. Mixer's appointment to the Board of Directors, she and NxStage will enter into NxStage's standard form of indemnification agreement for directors, the form of which was previously filed as Exhibit 10.21 to NxStage's registration statement on Form S-1 (File No. 333-126711).

A copy of NxStage's November 9, 2012 press release announcing Ms. Mixer's appointment is attached hereto as Exhibit 99.1 and is incorporated in this report by reference.

(d) Exhibits

                  Exhibit
                  Number    Description

                  99.1      Press Release dated November 9, 2012