EXHIBIT 5.1


             [LETTERHEAD OF BALLARD SPAHR ANDREWS & INGERSOLL, LLP]


                                 April 22, 1999


AMB Property Corporation
505 Montgomery Street
San Francisco, California 94111

            Re:   Registration Statement on Form S-3

Ladies and Gentlemen:

            We have served as Maryland counsel to AMB Property Corporation, a
Maryland corporation (the "Company"), in connection with the registration with
the Securities and Exchange Commission (the "Commission") of up to 3,000,000
shares (the "Shares") of common stock, par value $.01 per share (the "Common
Stock"), of the Company covered by the Registration Statement (as defined
herein). The Shares are to be issued by the Company in accordance with the
Dividend Reinvestment and Direct Purchase Plan (the "Plan").

            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 (collectively, the "Documents"):

            1. The Registration Statement on Form S-3 (the "Registration
Statement"), in substantially the form filed or to be filed by the Company with
the Commission (the "Commission") under the Securities Act of 1933, as amended,
and the related form of prospectus, pursuant to which the Shares are to be
issued;

            2. The Plan;

            3. The charter of the Company (the "Charter");

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

AMB Property Corporation
April 22, 1999
Page 2

            5. Resolutions adopted by the Board of Directors of the Company on
or as of December 4, 1998, authorizing, among other things, the Plan, the
issuance of the Shares under the Plan and the filing of the Registration
Statement with the Commission;

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

            7. A certificate executed by an officer of the Company, dated as of
a recent date; and

            8. 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. 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
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 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.
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April 22, 1999
Page 3


            4. The Shares have not and will not be issued in violation of any
restriction on transfer contained in the Charter.

            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 formed and existing under and
by virtue of the laws of the State of Maryland and is in good standing with the
SDAT.

            2. The Shares have been duly authorized for issuance and, when and
if issued and delivered in accordance with the Plan and the Resolutions in
exchange for the consideration therefore, 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. We consent to the filing
of this opinion as an exhibit to the Registration Statement and to the use of
the name of our firm in the section entitled "Legal Matters" in the Registration
Statement. In giving this consent, we do not admit that we are

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April 22, 1999
Page 4

within the category of persons whose consent is required by Section 7 of the
1933 Act.

                                    Very truly yours,

                                    /s/ BALLARD SPAHR ANDREWS & INGERSOLL, LLP