SecProbe.io

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

       DIVISION OF
CORPORATION FINANCE

April 12, 2012

Via E-mail
Mr. Mark P. de Raad Executive Vice President and Chief Financial Officer Masimo Corporation 40 Parker Irvine, California 92618   RE: Masimo Corporation
  Form 10-K for Fiscal Ye ar Ended December 31, 2011
  Filed February 17, 2012   Form 8-K Dated February 14, 2012   Filed February 14, 2012
File No. 001-33642

Dear Mr. de Raad:
We have reviewed your filing and have the following comments.  We have limited
our review to only your financial statements and related disclosures and do not intend to
expand our review to other portions of your documents.  In some of our comments, we may
ask you to provide us with information so we may better understand your disclosure.

Please respond to this letter within ten business days by providing the requested
information, or by advising us when you will provide the requested response. If you do not
believe our comments apply to your facts and circumstances please tell us why in your
response.
After reviewing the information you provide in response to these comments, we may
have additional comments.

Mark P. de Raad
Masimo Corporation April 12, 2012 Page 2
 Form 10-K for the Fiscal Year Ended December 31, 2011

 Management’s Discussion and Analysis of Financial Condition and Results of
Operations, page 52
 Critical Accounting Estimates, page 59

 Inventory/Reserves for Excess or  Obsolete Inventory, page 59

1. We see disclosures herein that you maintain a general inventory reserve  based on
your estimate of future limitations on your  ability to utilize the inventory on hand.
In light of the referenced disclosures, please tell us how your inventory valuation
policies comply with the gui dance at SAB Topic 5 (BB).

Form 8-K Dated and Filed February 14, 2012
 Item 2.02 and Item 9.01

 Exhibit 99.1

2. We see that in this exhibit you disclo se non-GAAP financial measures, including
“adjusted net income” and “adjusted EPS” as well as a percentage increase in
rainbow revenues excluding the U.S. military order.  However, we do not see where you provided the disclosures require d by Item 10(e)(1)(i) of Regulation S-
K.  With a view towards revised disclosure in future filings, please provide us with a revised Item 2.02 of your Form 8- K and a discussion of your results that
complies with Item 10(e)(1)(i) of Regulat ion S-K.  All reconciliations presented
should be sufficiently detailed to allow a reader to understand the nature of the
reconciling items.  In addition, please c onfirm that in future periods you will
comply with the requirements of Regul ation G whenever you publicly disclose
material information that incl udes a non-GAAP financial measure.

We urge all persons who are responsible for the accuracy and adequacy of the
disclosure in the filing to be certain that the filing includes the information the Securities Exchange Act of 1934 and all applicable Exchange Act rules require. Since the company and
its management are in possession of all facts relating to a company’s disclosure, they are
responsible for the accuracy and adequacy of the disclosures they have made.

In responding to our comments, please provide a written statement from the company
acknowledging that:

 the company is responsible for the adequacy and accuracy of the disclosure in the
filing;

Mark P. de Raad
Masimo Corporation April 12, 2012 Page 3
  staff comments or changes to disclosure in response to staff comments do not
foreclose the Commission from taking any action with respect to the filing; and
 the company may not assert staff comments as a defense in any proceeding initiated
by the Commission or any person under the federal securities laws of the United States.

You may contact Dennis Hult, Staff A ccountant, at (202) 551-3618 or Jay Webb,
Reviewing Accountant, at ( 202) 551-3603 if you have ques tions regarding comments on
the financial statements and related matters .  Please contact me at (202) 551-3212 with
any other questions.
Sincerely,
         / s /  J a y  W e b b  “ f o r ”
Jeffrey Jaramillo    Accounting Branch Chief
 cc: Jeff Hartlin, corporate counsel