
<PAGE>

                                                                     Exhibit 5.2


                                  May 22, 1998


Brandywine Realty Trust
16 Campus Boulevard
Newton Square, Pennsylvania 19073

         Re: Registration Statement on Form S-3
         --------------------------------------

Ladies and Gentlemen:

         We have served as Maryland counsel to Brandywine Realty Trust, a
Maryland real estate investment trust (the "Company"), in connection with
certain matters of Maryland law arising out of the registration of 597,572
common shares of beneficial interest, $.01 par value per share, of the Company
(the "Shares"), covered by a Registration Statement on Form S-3, and all
amendments thereto (the "Registration Statement"), under the Securities Act of
1933, as amended (the "1933 Act"). Unless otherwise defined herein, capitalized
terms used herein shall have the meanings assigned 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 (collectively, the "Documents"):

         1. The Registration Statement and the related form of prospectus
included therein in the form in which it was transmitted to the Securities and
Exchange Commission under the 1933 Act;

         2. The Amended and Restated Declaration of Trust of the Company, as
amended (the "Declaration"), certified as of a recent date by the State
Department of Assessments and Taxation of Maryland (the "SDAT");

         3. The Bylaws of the Company, certified as of a recent date by its
Secretary;

         4. Resolutions adopted by the Board of Trustees of the Company relating
to the sale, issuance and registration of the Shares, certified as of a recent
date by the Secretary of the Company;

         5. The form of certificate evidencing common shares of beneficial
interest, $.01 par value per share, of the Company ("Common Shares"), certified
as of a recent date by the Secretary of the Company;

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

         7. A certificate executed May 22, 1998 by Brad A. Molotsky, Secretary
of the Company, which we have assumed is true and correct as of the date hereof;
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.



<PAGE>



         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.

         4. All Documents submitted to us as originals are authentic. All
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 or amendment to any of the
Documents, and there has been no waiver of any provision of the Documents, by
action or omission of the parties or otherwise.

         5. The Shares will not be transferred in violation of any restriction
or limitation contained in the Declaration.

         6. The Company will be in good standing with the SDAT on the date on
which the Shares are actually issued.

         7. Prior to the issuance of the Shares, the Board of Trustees of the
Company, or a duly authorized committee thereof, will adopt resolutions that
would, if the Company were a Maryland corporation, satisfy the requirements of
the Maryland General Corporation Law with respect to the issuance of shares of
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 real estate investment trust 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. Assuming that the sum of (a) all Common Shares issued as of the date
hereof (not including any of the Shares), (b) any Common Shares issued between
the date hereof and the date on which any of the Shares are actually issued (not
including any of the Shares), and (c) the Shares will not exceed the total
number of Common Shares that the Company is then authorized to issue, the Shares
are duly authorized and will, upon issuance in accordance with their terms and
resolutions of the Board of Trustees of the Company authorizing their issuance,
be validly issued, fully paid and nonassessable.

         The foregoing opinion is limited to the laws of the State of Maryland
and we do not express any opinion herein concerning any other law. We express no
opinion as to compliance with the securities (or "blue sky") laws or the real
estate syndication laws of the State of Maryland.

         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 solely for submission to the
Securities and Exchange 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 Pepper Hamilton LLP, counsel
to the Company) without, in each instance, our prior written consent.




<PAGE>



         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,

                                 /s/ Ballard Spahr Andrews & Ingersoll, LLP
                                 ------------------------------------------
                                 Ballard Spahr Andrews & Ingersoll, LLP



