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                                                                   Exhibit 8.1






                                                     February 20, 1998


Brandywine Realty Trust
16 Campus Boulevard
Newtown Square, Pennsylvania 19073

Gentlemen:

         We have acted as Tax Advisor to Brandywine Realty Trust (the
"Company"), in connection with the preparation of a registration statement on
Form S-3 (the "Registration Statement"), filed with the Securities and Exchange
Commission on February 20, 1998, with respect to the offering and sale (the
"Offering") of common shares of beneficial interest (the "Shares") of the
Company. You have requested our opinion on certain federal income tax matters in
connection with the Offering. Capitalized terms not otherwise defined herein
shall have the meaning set forth in the Registration Statement.

         In rendering the opinions expressed herein, we have examined such
documents and other matters as we have deemed necessary or appropriate,
including (but not limited to) the Registration Statement and the Prospectus,
representation letters provided by the Company to us, and schedules prepared by
the Company which relate to the Company's compliance with various REIT
qualification tests. Further, we have obtained additional information and
representations from officers of the Company with respect to various factual
matters relating to the Company's operations and stock ownership and to the
Company's expectations to continue to meet certain diversity of ownership tests
on a basis consistent with past practice and of its intention to operate in a
manner consistent with its past operations, subject to any changes described in
the Prospectus. We have relied on the opinion of Pepper Hamilton LLP that the
shares of Non-Voting Preferred Stock issued by Brandywine Realty Services
Corporation to Brandywine Operating Partnership, L.P. do not constitute voting
securities for purposes of the Investment Company Act of 1940. We have also
relied on good standing certificates obtained from the Secretary of State that
certain partnerships are in good standing under the laws of their respective
jurisdiction of formation. In addition, we have relied upon the authenticity of
the documents, and upon the accuracy of the representations, described above.

         Our past material professional relationship with the Company has
consisted of rendering opinions on the Company's financial statements under
generally accepted accounting principles from 1986 through the calendar
year-ending December 31, 1996. In addition, we prepared the Company's federal
and state tax returns from 1986 through 1988 and 1996.

         Based upon and subject to the foregoing, it is our opinion that:

         1. The descriptions of the federal income tax conclusions contained in
the Prospectus under the caption "Federal Income Tax Considerations" are correct
in all material respects, and the discussion contained therein fairly summarizes
the federal income tax considerations that may be material to a holder of the
Shares and Warrants.

         2. The Operating Partnership and the Title Holding Partnerships have at
all times been and will continue to be treated for federal income tax purposes
as partnerships and not as associations taxable as corporations or as publicly
traded partnerships.

         3. Beginning with its taxable year ended December 31, 1986, the company
was organized and has operated in conformity with the requirements for
qualification as a REIT under the Code for each of its taxable years and the
Company's current method of organization and operation will enable it to
continue to so qualify.
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         The opinion expressed herein is based upon the Code, the Treasury
Department's regulations which interpret the Code, and relevant judicial and
administrative precedent, all of which are subject to change, on a retroactive
basis, at any time. Any such changes could adversely impact the opinion rendered
herein and the tax consequences to the Company and the investors in the Shares
and Warrants. During the course of our engagement, after reasonable
investigation, nothing has come to our attention which would cause us to
question the accuracy of the documents or other information provided to us by
the Company or the veracity of the information or representations provided to us
by the Company or Company's counsel. As noted above, the examination of these
documents, the accumulation of the information contained therein and
representations of the Company and its counsel formed a material part of the
basis on which we formed our opinion. Should anything occur, or already have
occurred, that would compromise the accuracy of the aforementioned documents or
the veracity of the aforementioned information and representations, our opinion
as expressed herein may not be relied upon.

         Our opinion is valid as of the date of this letter. We have not been
retained, nor are we obligated, to monitor or update this opinion for future
conditions that may affect this opinion. Our opinion is limited to the tax
matters specifically enumerated within and we have not considered any other
federal income tax matters, any state or local income tax issues, nor any non
U.S. tax issues, potentially impacting upon an investment in the Shares and
Warrants. Potential investors in the Shares and the Warrants are urged to seek
and rely on the tax advice of a qualified professional. The opinion expressed
herein is not binding upon the IRS and should not be construed to indicate IRS
approval of the Company's qualifying status as a REIT for the years considered
herein. The opinions expressed herein reflect our assessment of the outcome of
litigation and other adversarial proceedings based on an analysis of the
existing tax authorities relating to the issues. It is important to note,
however, no assurances can be given that the Company would in fact litigate any
of the matters addressed herein.

         We understand that our opinion will be attached as an Exhibit to the
Registration Statement and will be referred to in the Prospectus that is part of
the Registration Statement which will be delivered to prospective purchasers of
the Shares and Warrants, and we hereby consent to such use of our opinion.


                                                     ARTHUR ANDERSEN LLP

