Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF 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 *
  Maniwa Tetsuro
 2. Date of Event Requiring Statement (Month/Day/Year)
05/02/2008		 3. Issuer Name and Ticker or Trading Symbol
MASIMO CORP [MASI]
(Last)
(First)
(Middle)
C/O MASIMO CORPORATION 40 PARKER		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
President, Masimo Japan
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

IRVINE, CA 92618		 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 Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Non-qualified stock option (right to buy)   (1) 05/24/2017 Common Stock 60,000 $ 15.4 D  
Non-qualified stock option (right to buy)   (2) 07/18/2017 Common Stock 1,000 $ 16 I Family member (3)

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Maniwa Tetsuro
C/O MASIMO CORPORATION 40 PARKER
IRVINE, CA 92618		       President, Masimo Japan  

Signatures

/s/ Mark P. de Raad 05/12/2008
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(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) This option was granted on May 24, 2007 and is exercisable as the option vests. This option vests over a five-year period, with 20% of the shares subject to the option vesting on each anniversary of the grant date.
(2) This option was granted on July 18, 2007 and is exercisable as the option vests. This option vests over a five-year period, with 20% of the shares subject to the option vesting on each anniversary of the grant date.
(3) Shares held directly by a family member of Mr. Maniwa for which Mr. Maniwa has voting or investment power.
 
Remarks:
Exhibit 24 Power of Attorney

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