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 *
BERG CARL E
   2. Issuer Name and Ticker or Trading Symbol
MISSION WEST PROPERTIES INC [MSW] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director __X__ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
CEO
(Last)
(First)
(Middle)
C/O BERG & BERG DEVELOPERS, 10050 BANDLEY DR		 3. Date of Earliest Transaction (Month/Day/Year)
04/17/2009
(Street)

CUPERTINO, CA 95014		 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

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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
LIMITED PARTNERSHIP UNITS "LP UNITS" (1) (2) (6) $ 0 04/17/2009   G     22,000 12/28/1999 12/31/2048 COMMON STOCK 22,000 $ 0 32,036,355 D  
LP UNITS (1) (3) (6) $ 0             12/28/1999 12/31/2048 COMMON STOCK 10,789,383   10,789,383 D  
LP UNITS (1) (4) (6) $ 0             12/28/1999 12/31/2048 COMMON STOCK 196,428   196,428 D  
LP UNITS (1) (5) (6) $ 0             12/28/1999 12/31/2048 COMMON STOCK 169,131   169,131 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
BERG CARL E
C/O BERG & BERG DEVELOPERS
10050 BANDLEY DR
CUPERTINO, CA 95014		   X   X   CEO  

Signatures

 CARL E. BERG, AS AN INDIVIDUAL AND AS AN OFFICER OF REPORTING GROUP MEMBERS   04/24/2009
**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) LP UNITS BECAME EXCHANGEABLE FOR COMMON STOCK ON OR AFTER DECEMBER 28, 1999 UNDER THE TERMS OF THE EXCHANGE RIGHTS AGREEMENT DATED DECEMBER 28, 1998 BETWEEN THE COMPANY AND THE LP UNITHOLDERS. LP UNITS MAY BE EXCHANGED FOR AN EQUAL NUMBER OF SHARES OF THE COMPANY'S COMMON STOCK, OR AT THE ELECTION OF THE COMPANY, CASH EQUAL TO THE FAIR MARKET VALUE OF THE SHARES. THESE REPORTING PERSONS AND OTHER PERSONS WHO ARE MEMBERS OF THE BERG GROUP ARE SUBJECT TO AN AGGREGATE OWNERSHIP LIMIT EQUAL TO 20% OF THE OUTSTANDING SHARES OF COMMON STOCK, WHICH REPRESENTS A CONVERSION CAP ON THE TOTAL NUMBER OF SHARES THAT CAN BE ACQUIRED BY ANY REPORTING PERSON AND ALL REPORTING PERSONS COMBINED. LP UNITS ARE CONVERTIBLE TO COMMON STOCK ON A 1:1 BASIS.
(2) THESE LP UNITS ARE OWNED BY CARL E. BERG, THE DESIGNATED BENEFICIAL OWNER FOR THE REPORTING GROUP. ON APRIL 17, 2009, CARL E. BERG CONTRIBUTED 22,000 LP UNITS TO A QUALIFYING CHARITABLE ORGANIZATION.
(3) THESE LP UNITS ARE OWNED BY BERG & BERG ENTERPRISES, INC., A MEMBER OF THE REPORTING GROUP WHOSE ADDRESS IS 10050 BANDLEY DRIVE, CUPERTINO, CA 95014.
(4) THESE LP UNITS ARE OWNED BY BERG & BERG ENTERPRISES, LLC, A MEMBER OF THE REPORTING GROUP WHOSE ADDRESS IS 10050 BANDLEY DRIVE, CUPERTINO, CA 95014.
(5) THESE LP UNITS ARE OWNED BY WEST COAST VENTURE CAPITAL, INC., A MEMBER OF THE REPORTING GROUP WHOSE ADDRESS IS 10050 BANDLEY DRIVE, CUPERTINO, CA 95014.
(6) THE DESIGNATED BENEFICIAL OWNER DISCLAIMS BENEFICIAL OWNERSHIP OF ALL SECURITIES REPORTED ON THIS FORM 4. ALL REPORTING PERSONS DISCLAIM BENEFICIAL OWNERSHIP OF ALL SECURITIES EXCEPT TO THE EXTENT OF THEIR RESPECTIVE PECUNIARY INTERESTS THEREIN.

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