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                                                                     EXHIBIT 5.1


[BALLARD SPAHR ANDREWS & INGERSOLL LETTERHEAD]


November 19, 1997


AMB Property Corporation
505 Montgomery Street
San Francisco, California 94111

        Re:     AMB Property Corporation, a Maryland corporation to be formed,
                (the "Company") - Registration Statement on Form S-11 pertaining
                to Thirteen Million Eight Hundred Thousand (13,800,000) shares
                of common stock, par value one cent ($.01) per share (the
                "Shares")

Ladies and Gentlemen:

        In connection with the registration of the Shares under the Securities
Act of 1933 as amended (the "Act"), by the Company on Form S-11 filed with the
Securities and Exchange Commission (the "Commission") on or about September 18,
1997, as amended (the "Registration Statement"), you have requested our opinion
with respect to the matters set forth below.

        We have acted as special Maryland corporate counsel to the Company in
connection with the matters described herein. In our capacity as special
Maryland corporate counsel to the Company and for purposes of this letter, we
have examined the following documents: (i) the corporate charter of the Company
(the "Charter") represented by a copy of the Articles of Incorporation which are
to be filed with the State Department of Assessments and Taxation of Maryland
(the "SDAT") on or before November 26, 1997 (the actual date of such filing is
hereinafter referred to as the "Incorporation Date"); (ii) the bylaws of the
Company (the "Bylaws") which are to be adopted on the Incorporation Date; (iii)
resolutions of the Board of Directors of the Company (the "Directors'
Resolutions"), and resolutions of the sole stockholder of the Company (the
"Stockholder's Resolutions") which are to be adopted on the Incorporation Date;
(iv) the Registration Statement; and (v) such other documents and matters as we
have deemed necessary or appropriate to express the opinions set forth in this
letter, subject to the assumptions, limitations and qualifications stated
herein.

        In reaching the opinions set forth below, we have assumed the following:
(a) all documents submitted to us as originals are authentic; all documents
submitted to us as certified, facsimile or photostatic copies conform to the
original documents; all signatures on all documents submitted to us for
examination are genuine all statements and information contained therein are
true and correct; and all public records reviewed are accurate and complete; (b)
the Company will be incorporated by the filing of the charter, in the form
reviewed by us with no modifications or revisions, with the SDAT, and the
acceptance of the Charter for record by the SDAT on the Incorporation Date; (c)
the Bylaws and the Directors' Resolutions, in the forms reviewed by us with no
modifications or revisions, will be duly adopted by the Board of Directors of
the Company on the Incorporation Date, subsequent to the incorporation of the
Company, and the actions authorized by the Directors' Resolutions will be
carried out by the Company in a timely manner including, but not limited to, the
issuance of shares of stock to the sole stockholder of the Company; on the
Incorporation Date; (d) the Stockholder's Resolutions, in the form reviewed by
us with no modifications or revisions, will be duly adopted by the sole
stockholder of the Company on the Incorporation Date, subsequent to the
incorporation of the Company and the adoption of the Directors' Resolutions; and
(e) none of the Shares will be issued or transferred in violation of the
provisions of Section (e) of Article IV of the Charter entitled "Restrictions on
Ownership and Transfer to preserve tax benefits".
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        Based on the foregoing, and subject to the assumptions and
qualifications set forth herein, it is our opinion that as of the Incorporation
Date, the Shares will have been duly authorized by all necessary corporation
action on the part of the Company, and the Shares will, upon issuance and
delivery in accordance with the subject to the terms and conditions described in
the Registration Statement against payment of the purchase price therefore as
determined by the Board of Directors of the Company or a committee thereof, be
validly issued, fully paid and nonassessable.


        We consent to your filing this opinion as an exhibit to the Registration
Statement, and further consent to the filing of this opinion as an exhibit to
the applications to securities commissioners for the various states of the
United States for registration of the Shares. We also consent to the
identification of our firm as Maryland counsel to the Company in the section of
the Prospectus (which is part of the Registration Statement) entitled "Legal
Matters."

        The opinions expressed herein are limited to the laws of the State of
Maryland and we express no opinion concerning any laws other than the laws of
the State of Maryland. Furthermore, the opinions presented in this letter are
limited to the matters specifically set forth herein and no other opinion shall
be inferred beyond the matters expressly stated.

                                        Very truly yours,

                                        /s/ BALLARD SPAHR ANDREWS & INGERSOLL
