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

                                  FORM 12b-25

                           NOTIFICATION OF LATE FILING

                          Commission File Number 1-8383


(CHECK ONE): [ ] Form 10-K [ ] Form 20-F [ ] Form 11-K [X] Form 10-Q
             [ ] Form N-SAR [ ] Form N-CSR

                 For Period Ended:     June 30, 2004
                 [ ] Transition Report on Form 10-K
                 [ ] Transition Report on Form 20-F
                 [ ] Transition Report on Form 11-K
                 [ ] Transition Report on Form 10-Q
                 [ ] Transition Report on Form N-SAR
                 For the Transition Period Ended:

         READ INSTRUCTIONS BEFORE PREPARING FORM. PLEASE PRINT OR TYPE.

Nothing  in this  form  shall be  construed  to imply  that the  Commission  has
verified any information contained herein.

If the notification  relates to a portion of the filing checked above,  identify
the Item(s) to which the notification relates:


PART I -- REGISTRANT INFORMATION

Mission West Properties, Inc.
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Full Name of Registrant

N/A
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Former Name if Applicable

10050 Bandley Drive
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Address of Principal Executive Office (Street and Number)

Cupertino, CA 95014
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City, State and Zip Code


PART II -- RULES 12b-25(b) AND (c)

If the subject report could not be filed without  unreasonable effort or expense
and the registrant seeks relief pursuant to Rule 12b-25(b), the following should
be completed. (Check box if appropriate)

[X]  (a) The  reason  described  in  reasonable  detail in Part III of this form
     could not be eliminated without unreasonable effort or expense

[X]  (b) The subject annual report,  semi-annual  report,  transition  report on
     Form 10-K,  Form  20-F,  Form 11-K,  Form N-SAR or Form  N-CSR,  or portion
     thereof,  will be filed on or before the  fifteenth  calendar day following
     the  prescribed  due date;  or the subject  quarterly  report or transition
     report on Form  10-Q,  or portion  thereof,  will be filed on or before the
     fifth calendar day following the prescribed due date; and

[ ]  (c)   The  accountant's  statement  or   other  exhibit  required  by  Rule
     12b-25(c) has been attached, if applicable.







PART III -- NARRATIVE

State below in reasonable detail why Forms 10-K, 20-F, 11-K, 10-Q, N-SAR, N-CSR,
or the  transition  report or  portion  thereof,  could not be filed  within the
prescribed time period.

(Attach extra sheets if needed)

The  Registrant's  Quarterly  Report on Form 10-Q for the quarter ended June 30,
2004  could  not  be  filed  within  the  prescribed  time  period  because  its
independent accountant,  PricewaterhouseCoopers LLP, San Francisco,  California,
previously engaged as the principal accountant to audit the financial statements
of Mission West  Properties,  Inc.,  (the  "Company"),  resigned as  independent
auditors for the Company on January 26, 2004 and withdrew its  association  with
the Company's financial  statements for 2001 and 2002 for which such independent
accountant had issued its report of independent auditors previously. BDO Seidman
LLP ("BDO"),  the Company's new independent  registered  public accounting firm,
commenced their engagement on May 10, 2004 and issued their report of registered
independent  public  accountants  for 2001,  2002 and 2003 on July 27, 2004. The
Company filed its 2003 Form 10-K on July 30, 2004. The Company is simultaneously
preparing  Quarterly  Reports on Form 10-Q for the quarters ended March 31, 2004
and June 30,  2004 for review by BDO but cannot  complete  this work  within the
prescribed  time for filing the subject  report without  unreasonable  effort or
expense.


PART IV -- OTHER INFORMATION

(1)  Name  and  telephone  number  of  person  to  contact  in  regard  to  this
     notification

   Carl E. Berg                   408                      725-0700
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      (Name)                   (Area Code)           (Telephone Number)

(2)  Have all other periodic  reports  required under Section 13 or 15(d) of the
     Securities Exchange Act of 1934 or Section 30 of the Investment Company Act
     of 1940 during the preceding 12 months or for such shorter  period that the
     registrant  was required to file such  report(s)  been filed ? If answer is
     no, identify report(s).
                                                                  Yes [ ] No [X]

     Form 10-K for calendar year 2003 was filed on July 30, 2004.  Form 10-Q for
     the quarter  ended March 31, 2004 has not been filed.  The Company plans to
     file this Quarterly Report by August 12, 2004.

(3)  Is it anticipated that any significant change in results of operations from
     the corresponding  period for the last fiscal year will be reflected by the
     earnings  statements  to be  included  in the  subject  report  or  portion
     thereof?
                                                                    Yes[ ] No[X]

If so, attach an explanation of the  anticipated  change,  both  narratively and
quantitatively, and, if appropriate, state the reasons why a reasonable estimate
of the results cannot be made.

                          MISSION WEST PROPERTIES, INC.
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                  (Name of Registrant as Specified in Charter)

has  caused  this  notification  to be signed on its  behalf by the  undersigned
hereunto duly authorized.

Date  August 9, 2004                    By  /s/ Carl E. Berg
     --------------------------           -------------------------
                                          Carl E. Berg
                                          Chief Executive Officer