Ownership Submission
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 *
Turk Joseph E Jr
   2. Issuer Name and Ticker or Trading Symbol
NxStage Medical, Inc. [NXTM] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
President, North America
(Last)
(First)
(Middle)
C/O NXSTAGE MEDICAL, INC., 439 SOUTH UNION STREET, 5TH FLOOR		 3. Date of Earliest Transaction (Month/Day/Year)
03/09/2012
(Street)

LAWRENCE, MA 01843		 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
Common Stock 03/09/2012   A   5,932 (1) A $ 0 90,432 D  
Common Stock 03/09/2012   M   3,056 (2) A $ 0 93,488 D  
Common Stock 03/09/2012   F(3)   2,853 D $ 18.48 90,635 D  

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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
Restricted Stock Unit (4) 03/09/2012   A   9,168     (5)   (5) Common Stock 9,168 $ 0 9,168 D  
Restricted Stock Unit (4) 03/09/2012   M     3,056   (5)   (5) Common Stock 3,056 $ 0 6,112 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Turk Joseph E Jr
C/O NXSTAGE MEDICAL, INC.
439 SOUTH UNION STREET, 5TH FLOOR
LAWRENCE, MA 01843		       President, North America  

Signatures

 /s/Winifred L. Swan, attorney-in-fact   03/13/2012
**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) In March 2011, the Compensation Committee of the Board of Directors (the "Compensation Committee") established the NxStage Medical, Inc. (the "Company") 2011 Corporate Bonus Plan with the amount of awards to be determined based upon the satisfaction of 2011 revenue, cash generation and net income targets. On March 9, 2012, the Compensation Committee awarded the reporting person 5,932 shares of common stock based on its evaluation of the achievement of performance criteria established under the 2011 Corporate Bonus Plan.
(2) Shares of common stock acquired upon the vesting of restricted stock units.
(3) This transaction reflects the withholding of shares of the Company's common stock to satisfy the reporting person's tax liability incurred in connection with the common stock granted to the reporting person on March 9, 2012 pursuant to the Company's 2011 Corporate Bonus Plan and the vesting of the first tranche of restricted stock units (the "Award") on March 9, 2012 pursuant to the Company's 2011 Performance Share Plan.
(4) Each restricted stock unit represents a contingent right to receive one share of the Company's common stock.
(5) In March 2011, the Compensation Committee established the Company's 2011 Performance Share Plan with the amount of awards to be determined based upon the satisfaction of 2011 revenue, cash generation and net income targets. On March 9, 2012, the Compensation Committee granted the reporting person 9,168 restricted stock units, the Award, based on its evaluation of the achievement of performance criteria under the Company's 2011 Performance Share Plan. The Award vested 33 1/3rd% on March 9, 2012, with the balance vesting in two equal installments on March 9, 2013 and March 9, 2014.

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