Exhibit 10.31

AMENDMENT NO.1 TO LEASE AGREEMENT
THIS AMENDMENT NO. 1 TO LEASE is made and entered into as of November 12, 2009,
by and between THE NORTHWESTERN MUTUAL LIFE INSURANCE COMPANY, a Wisconsin
corporation (“Lessor”), and MASIMO CORPORATION, a Delaware corporation
(“Lessee”), with respect to the following facts:    
RECITALS
A.     Lessor and Lessee have heretofore made and entered into that certain
Standard Industrial/Commercial Single-Tenant Lease - Modified Net (the “Lease”),
dated April 30, 2009, with respect to those certain Premises located at 40
Parker, Irvine, California.
B.     Lessor and Lessee desire to modify the Commencement Date of said Lease by
changing it from November 1, 2009, to December 1, 2009.
TERMS AND CONDITIONS
NOW THEREFORE, in consideration of the foregoing recitals, the mutual covenants
contained herein, and other good and valuable consideration, receipt and
sufficiency of which is hereby acknowledged, the parties agree as follows:
1.     Commencement Date of Lease Term. Lessor and Lessee agree that Paragraph
1.3 of the Lease shall be amended by changing the Commencement Date to December
1, 2009. Accordingly, the fees due under Paragraph 1.7(a) in the amount of
$49,153.50 for Base Rent and under Paragraph 1.7(b) in the amount of $14,700.44
for Common Area Operating Expenses, Insurance and Real Property Taxes shall be
used for the month of December 2009. The Expiration Date of the Lease shall
remain September 30, 2014, and the schedule for monthly base rent adjustments
shall remain as set forth in Paragraph 57 of the Lease Addendum.
2.     No Other Changes. Except as expressly set forth herein, the Lease remains
in full force and effect without any change or alteration of any nature
whatsoever.
IN WITNESS WHEREOF, this Agreement has been entered into by the parties as of
the date first above written.

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THE NORTHWESTERN MUTUAL LIFE INSURANCE COMPANY, a Wisconsin corporation
 
MASIMO CORPORATION, a Delaware corporation
By:
Northwestern Investment Management Company, LLC, Delaware limited liability
company, its wholly-owned affiliate and authorized representative
 
By:
MASIMO CORPORATION, a Delaware corporation
 
 
 
 
 
By:
/s/ Don Morton
 
By:
/s Yongsam Lee
Printed Name:
Don Morton
 
Printed Name:
Yongsam Lee
Its:
Director - Field Asset Management
 
Its:
CIO
Date:
November 19, 2009
 
Date:
November 11, 2009