[Ballard Spahr Andrews & Ingersoll Letterhead]




           We have served as Maryland counsel to Mission West Properties,  Inc.,
a Maryland  corporation (the  "Company"),  in connection with certain matters of
Maryland law arising out of the merger of Mission West Properties,  a California
corporation  and the sole  stockholder  of the Company with and into the Company
(the "Reincorporation  Merger"), the conversion of shares of the Common Stock of
Mission  West  California  into shares of the  Company's  common stock $.001 par
value (the "New Common  Stock")  and the  registration  of the New Common  Stock
under the Securities Act of 1933, as amended (the "1933 Act"),  all as described
in the above-referenced  Registration  Statement under the 1933 Act. Capitalized
terms used but not defined  herein shall have the meanings  given to them in the
Registration Statement.

           In connection with our representation of the Company,  and as a basis
for the opinion  hereinafter  set forth, we have examined  originals,  or copies
certified  or  otherwise  identified  to  our  satisfaction,  of  the  following
documents (hereinafter collectively referred to as the "Documents"):

           1.  The  Registration  Statement,   including  the  related  form  of
prospectus  included  therein,  in the form in which it was  transmitted  by the
Company to the Securities and Exchange  Commission (the "Commission")  under the
1933 Act;

           2. The Articles of  Incorporation  of the company,  certified as of a
recent date by the State  Department  of  Assessments  and  Taxation of Maryland
("SDAT");

           3. Proposed Articles of Amendment and Restatement of the Company,  in
the form attached to the Registration  Statement as Exhibit 3.2.1 (the "Articles
of Amendment and Restatement");

           4. The Bylaws of the  Company,  certified as of the date hereof by an
officer of the Company;

           5.  Resolutions  adopted  by the Board of  Directors  of the  Company
relating to the  approval of the  Articles of  Amendment  and  Restatement,  the
authorization of the Reincorporation Merger and the issuance and registration of
the New Common Stock (the "Board of Resolutions") and resolutions adopted by the
stockholders  of the  Company  relating  to the  approval  of  the  Articles  of
Amendment and  Restatement and the approval of the  Reincorporation  Merger (the
"Stockholders  Resolutions",  and,  together  with the  Board  Resolutions,  the
"Resolutions"), certified as of the date hereof by an officer of the Company;

           6. The form of  certificate  representing  a share of the New  Common
Stock;

           7. A  certificate  of the SDAT,  as of a recent date,  as to the good
standing of the Company;

           8. A  certificate  executed by an officer of the  Company,  dated the
date hereof;

           9. The Merger Agreement and Plan of Merger,  certified as of the date
hereof by an officer of the Company; and

           10. Such other  documents and matters as we have deemed  necessary or
appropriate  to express  the opinion  set forth in this  letter,  subject to the
assumptions, limitations and qualifications stated herein.

           In expressing  the opinion set forth below,  we have assumed,  and so
far as is known to us there are no facts inconsistent with, the following:

           1. Each individual executing any of the Documents,  whether on behalf
of such individual or another person, is legally competent to do so.

           2. Each  individual  executing  any of the  Documents  on behalf of a
party (other than the Company) is duly authorized to do so.

           3. Each of the parties (other than the Company)  executing any of the
Documents has duly and validly  executed and delivered  each of the Documents to
which such party is a signatory,  and such party's obligations set forth therein
are legal,  valid and binding and are  enforceable in accordance with all stated
terms.

           4. Any Documents submitted to us as originals are authentic. The form
and content of any Documents  submitted to us as unexecuted drafts do not differ
in any  respect  relevant  to this  opinion  from the form and  content  of such
Documents as executed and delivered.  Any Documents submitted to us as certified
or photostatic copies conform to the original  documents.  All signatures on all
such Documents are genuine.  All public records reviewed or relied upon by us or
on our behalf are true and complete. All statements and information contained in
the  Documents  are  true  and  complete.  There  has  been no  oral or  written
modification  of or  amendment  to any of the  Documents,  and there has been no
waiver of any  provision of any of the  Documents,  by action or omission of the
parties or otherwise.

           5. Articles of Amendment and  Restatement  authorizing the Company to
issue up to  200,000,000  shares of common stock and otherwise in  substantially
the form attached to the  Registration  Statement as Exhibit 3.2.1 will be filed
with and accepted for record by the SDAT prior to the issuance of the New Common
Stock.

           The phrase "known to us" is limited to the actual knowledge,  without
independent  inquiry,  of the  lawyers  at our  firm who  have  performed  legal
services in connection with the issuance of this opinion.

           Based upon the foregoing, and subject to the assumptions, limitations
and qualifications stated herein, it is our opinion that:

           1. The Company is a corporation duly  incorporated and existing under
and by virtue of the laws of the State of Maryland and is in good  standing with
the SDAT.

           2. The New Common Stock is duly  authorized  and,  when and if issued
and delivered  against  payment  therefor in accordance with the Resolutions and
the Merger Agreement and Plan of Merger, will be validly issued,  fully paid and
nonassessable.

           The foregoing opinion is limited to the substantive laws of the State
of Maryland,  and we do not express any opinion herein concerning any other law.
We express no opinion as to the  applicability or effect of any federal or state
securities laws,  including the securities laws of the State of Maryland,  or as
to federal or state laws regarding fraudulent transfers.  To the extent that any
matter as to which our  opinion is  expressed  herein  would be  governed by any
jurisdiction other than the State of Maryland,  we do not express any opinion on
such matter.

           We assume no obligation to supplement  this opinion if any applicable
law changes  after the date hereof or if we become  aware of any fact that might
change the opinion expressed herein after the date hereof.

           This  opinion  is  being  furnished  to  you  for  submission  to the
Commission as an exhibit to the registration Statement and, accordingly, may not
be relied upon by,  quoted in any manner to, or delivered to any other person or
entity (other than Graham & James LLP, counsel to the Company) without,  in each
instance, our prior written consent.

           We hereby  consent to the filing of this opinion as an exhibit to the
Registration Statement and to the use of the name of our firm therein. In giving
this  consent,  we do not admit that we are within the category of persons whose
consent is required by Section 7 of the 1933 Act.

Very Truly Yours,


Ballard Spahr Andrews & Ingersoll