UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

________________

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities and Exchange Act of 1934

Filed by the Registrant x

Filed by a Party other than the Registrant o

Check the appropriate box:

oPreliminary Proxy Statement

oConfidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

oDefinitive Proxy Statement

xDefinitive Additional Materials

oSoliciting Material Under Rule 14a-12

MISSION WEST PROPERTIES, INC.

(Name of Registrant as Specified In Its Charter)

_______________________________________________________

(Name of Person(s) Filing Proxy Statement, if other than Registrant)

Payment of Filing Fee (Check the appropriate box):

 x No fee required

 o Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11

(1) Title of each class of securities to which transaction applies:

(2) Aggregate number of securities to transaction applies:

(3) Per unit price or other underlying value of transaction computed pursuant to Exchange Act Rule 0-11(set forth the amount on which the filing fee is calculated and state how it was determined):

(4) Proposed maximum aggregate value of transaction:

(5) Total fee paid:

 o Fee paid previously with preliminary materials

 o Check box if any part of the fee is offset as provided by Exchange Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee was paid previously. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

(1) Amount Previously Paid:

(2) Form, Schedule or Registration Statement No.:

(3) Filing Party:

      (4)  Date Filed:

MISSION WEST PROPERTIES, INC.

__________________

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SOLICITED BY THE BOARD OF DIRECTORS

FOR THE 2010 ANNUAL STOCKHOLDERS’ MEETING

The undersigned hereby appoints Carl E. Berg and Raymond V. Marino, each with the power to appoint his substitute, and hereby authorizes them to represent and to vote all shares of common stock of Mission West Properties, Inc. (the “Company”) held of record by the undersigned in favor of each proposal designated on this Proxy Card and to vote the shares of the undersigned in their discretion with respect to other matters that properly come before the 2010 Annual Stockholders’ Meeting (the “Annual Meeting”) to be held on May 20, 2010 and any adjournment of the Annual Meeting.

THIS PROXY WHEN PROPERLY EXECUTED WILL BE VOTED AS DIRECTED.  IF NO DIRECTION IS GIVEN WITH RESPECT TO A PARTICULAR PROPOSAL, THIS PROXY WILL BE VOTED FOR EACH OF THE NOMINEES IN PROPOSAL 1 AND FOR PROPOSAL 2.

PLEASE MARK, DATE, SIGN, AND RETURN THIS PROXY CARD PROMPTLY, USING THE ENCLOSED ENVELOPE.  NO POSTAGE REQUIRED IF MAILED IN THE UNITED STATES.

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DETACH HERE

	x	Please mark vote as in this example
1.     Election of Directors    Nominees:  01 Carl E. Berg   02 William A. Hasler   03 Lawrence B. Helzel   04 Raymond V. Marino   05 Martin S. Roher    oVote FOR                                     oVote WITHHELD          all nominees                                        from all nominees                (except as marked)				2.     Ratify the selection of Burr Pilger Mayer, Inc. as our independent registered public accounting firm for the fiscal year ending December 31, 2010.   FOR                    AGAINST                ABSTAIN   o    o    o
Instructions: To withhold authority to vote for any indicated nominee, write the number(s) of the nominee(s) in the box provided below.         ____________________________________________         ____________________________________________				Such other business as may properly come before the meeting or any adjournment thereof.
_________________________________________________                       Name         _________________________________________________                                                        Street Address         _________________________________________________               City                           State                Country                 Zip Code			MARK HERE FOR ADDRESS CHANGE        o AND NOTE AT LEFT Please sign exactly as name appears hereon.  Joint owners should each sign.  Executors, administrators, trustees, guardians or other fiduciaries should give full title as such.  If signing for a corporation or other entity, please sign in full corporate or other entity name by a duly authorized officer.
oPlease check here if you plan on attending the 2010 Annual Stockholders’ Meeting.
Signature: ___________________________    Date: __________			Signature:______________________________ Date: _________________