Exhibit 4.7

                          REGISTRATION RIGHTS AGREEMENT


         THIS REGISTRATION RIGHTS AGREEMENT (this "Agreement") is made and
entered into as of September 28, 1998 by Corporate Office Properties Trust,
a Maryland real estate investment trust (the "Company"), for the benefit of (x)
persons issued shares of Common Stock of the Company ("Common Stock") pursuant
to the Contribution Agreement, the Asset Contribution Agreement and the
Development Agreements (each, as defined below), (y) persons issued shares of
Convertible Preferred Stock of the Company ("Preferred Stock") pursuant to the
Contribution Agreement, the Asset Contribution Agreement and the Development
Agreements, and (z) the respective successors, assigns, transferees and estates
of the persons identified in clauses (x) and (y) (herein referred to
collectively as the "Holders" and individually as a "Holder"). The Common Stock
and Preferred Stock issued and to be issued to the Holders pursuant to the
Contribution Agreement, the Asset Contribution Agreement and the Development
Agreements are herein sometimes collectively called the "Stock."

         WHEREAS, on the date hereof certain Holders have become the owner of
Stock upon the transfer of certain partnership interests and other assets
pursuant to the Contribution Agreement dated as of May 14, 1998 by and among the
Company, Corporate Office Properties, L.P. ("COP") and the Persons identified
therein as "Sellers", as the same may at any time be amended, modified and
supplemented and in effect (the "Contribution Agreement");

         WHEREAS, on the date hereof certain Holders have become the owner of
Stock upon the transfer of certain membership interests and other assets
pursuant to the Service Company Asset Contribution Agreement dated as of May 14,
1998 by and among COP and the Persons identified therein as "Seller" and
"Shareholders", as the same may at any time be amended, modified and
supplemented and in effect (the "Asset Contribution Agreement");

         WHEREAS, after the date hereof certain Holders may become the owner of
Stock upon the transfer of certain partnership interests and other assets
pursuant to two Development Properties Acquisition Agreements each dated as of
May 14, 1998 by and among the Company, COP and the Persons identified therein as
"Sellers", as the same may at any time be amended, modified and supplemented and
in effect (the "Development Agreements");

         WHEREAS, pursuant to the Company's Amended and Restated Declaration of
Trust, the Holders of shares of Preferred Stock have the right to convert them
into shares of Common Stock;

         WHEREAS, on the date hereof, the Common Stock is publicly held and
traded and the Company is an issuer which is subject to the reporting
requirements of the Securities Exchange Act of 1934, as amended from time to
time (the "Exchange Act");

         WHEREAS, in connection with the foregoing, the Company has agreed,
subject to the terms, conditions and limitations set forth in this Agreement, to
provide the Holders with certain registration rights in respect of shares of
Common Stock issued either (x) pursuant to the Contribution Agreement, the Asset
Contribution Agreement or the Development Agreements, or (y) upon conversion of
shares of Preferred Stock issued pursuant to the Contribution Agreement, the
Asset Contribution Agreement or the Development Agreements.


         NOW, THEREFORE, the Company for the benefit of the Holders agrees as
follows:

SECTION 1.        DEFINITIONS.

         As used in this Agreement, the following capitalized defined terms
shall have the following meanings:

         ASSET CONTRIBUTION AGREEMENT:  As set forth in the preamble.

         COMMISSION:  The Securities and Exchange Commission.

         COMMON STOCK:  Shares of common stock, $.01 par value, of the Company.

         CONTRIBUTION AGREEMENT:  As set forth in the preamble.

         DEVELOPMENT AGREEMENTS:   As set forth in the preamble.

         EXCHANGE ACT:  As set forth in the preamble.

         HOLDER OR HOLDERS:  As set forth in the preamble.

         MAJORITY HOLDERS: At any time, Holders of Registrable Securities and
shares of Preferred Stock then convertible into Registrable Securities who, if
all such Preferred Stock were converted, would then hold a majority of the
Registrable Securities.

         MINIMUM REGISTRABLE AMOUNT: At any date of determination, Registrable
Securities having an aggregate fair market value of at least $3 million.

         NASD:  The National Association of Securities Dealers, Inc.

         PERSON: Any individual, partnership, corporation, trust or other legal
entity.

         PREFERRED STOCK: Shares of Convertible Preferred Stock, par value
$25.00, of the Company.

         PROSPECTUS: A prospectus included in a Registration Statement,
including any preliminary prospectus, and any such prospectus as amended or
supplemented by any prospectus supplement with respect to the terms of the
offering of any portion of the Registrable Securities covered by such
Registration Statement, and by all other amendments and supplements to such
prospectus, including post-effective amendments, and in each case including all
material incorporated by reference therein.

         REGISTRABLE SECURITIES: The shares of Common Stock (i) issued pursuant
to the terms of the Contribution Agreement, the Asset Contribution Agreement and
the Development Agreements, and (ii) issued and issuable upon conversion of the
shares of Preferred Stock issued pursuant to the terms of the Contribution
Agreement, the Asset Contribution Agreement and the Development Agreements.
Registrable Securities shall not include (x) Common Stock as to which a
Registration Statement shall have become effective under the Securities Act
pursuant to Section 2, 3 or 4 of this Agreement and which shall have been
disposed of under such Registration



                                      -2-

Statement, (ii) Common Stock sold or otherwise distributed pursuant to Rule 144
under the Securities Act and (iii) Common Stock as to which registration under
the Securities Act is not required to permit the sale thereof to the public by a
Holder at any time and without application of any volume or other limitations
imposed by Rule 144 under the Securities Act.

         SALE PERIOD: The 60-day period immediately following the filing with
the Commission by the Company of an annual report of the Company on Form 10-K or
a quarterly report of the Company on Form 10-Q or such other period as the
Company may determine.

         SECURITIES ACT: The Securities Act of 1933, as amended from time to
time.

         SHELF REGISTRATION STATEMENT: shall mean a "shelf" registration
statement of the Company and any other entity required to be a registrant with
respect to such shelf registration statement pursuant to the requirements of the
Securities Act which covers all of the Registrable Securities then issued and
outstanding or which may thereafter be issued pursuant to the Contribution
Agreement, the Asset Contribution Agreement or the Development Agreements on an
appropriate form under Rule 415 under the Securities Act, or any similar rule
that may be adopted by the Commission, and all amendments and supplements to
such registration statement, including post-effective amendments, in each case
including the Prospectus contained therein, all exhibits thereto and all
materials incorporated by reference therein.



         SECTION 2. SHELF REGISTRATION UNDER THE SECURITIES ACT.

               (a) FILING OF SHELF REGISTRATION STATEMENT. Within six months
following, the date hereof, the Company shall cause to be filed a Shelf
Registration Statement providing for the sale by the Holders of all of the
Registrable Securities in accordance with the terms hereof and will use its
reasonable best efforts to cause such Shelf Registration Statement to be
declared effective by the SEC as soon as reasonably practicable. The Company
agrees to use its reasonable best efforts to keep the Shelf Registration
Statement continuously effective under the Securities Act until such time as the
aggregate number of Registrable Securities outstanding (computed for this
purpose as if all outstanding shares of Preferred Stock have been converted into
Common Stock) is less than 5% of the aggregate number of Registrable Securities
outstanding on the date hereof (assuming all Stock issuable pursuant to the
Development Agreements has been issued), and further agrees to supplement or
amend the Shelf Registration Statement, if and as required by the rules,
regulations or instructions applicable to the registration form used by the
Company for such Shelf Registration Statement or by the Securities Act or by any
other rules and regulations thereunder for Shelf Registration. Each Holder who
sells shares of Common Stock as part of the Shelf Registration shall be deemed
to have agreed to all of the terms and conditions of this Agreement and to have
agreed to perform any and all obligations of a Holder hereunder.

               (b) INCLUSION IN SHELF REGISTRATION STATEMENT. Not later than 30
days prior to filing the Shelf Registration Statement with the Commission, the
Company shall notify each Holder of its intention to make such filing and
request advice from each such Holder as to whether such Holder desires to have
Registrable Securities held by it or which it is entitled to receive not later
than the last day of the first Sale Period occurring in whole or in part after
the date of such notice included in the Shelf Registration Statement at such
time. Any such Holder 



                                      -3-

who does not provide the information reasonably requested by the Company in
connection with the Shelf Registration Statement as promptly as practicable
after receipt of such notice, but in no event later than 20 days thereafter,
shall not be entitled to have its Registrable Securities included in the Shelf
Registration Statement at the time it becomes effective, but shall have the
right thereafter to deliver to the Company a Registration Notice as contemplated
by Section 3(b) to have such Registrable Securities included in the Shelf
Registration Statement by post effective amendment.

         SECTION 3. SHELF REGISTRATION PROCEDURES.

         In connection with the obligations of the Company with respect to the
Shelf Registration Statement pursuant to Section 2 hereof, the Company shall:

               (a) prepare and file with the SEC, within the time period set
forth in Section 2(a) hereof, a Shelf Registration Statement, which Shelf
Registration Statement (i) shall be available for the sale of the Registrable
Securities in accordance with the intended method or methods of distribution by
the selling Holders thereof and (ii) shall comply as to form in all material
respects with the requirements of the applicable form.

               (b) subject to the last three sentences of this Section 3(b) and
to Section 3(i) hereof, (i) prepare and file with the Commission such amendments
and post-effective amendments to the Shelf Registration Statement as may be
necessary to keep the Shelf Registration Statement effective for the applicable
period; (ii) cause each Prospectus to be supplemented by any required prospectus
supplement, and as so supplemented to be filed pursuant to Rule 424 or any
similar rule that may be adopted under the Securities Act, (iii) respond
promptly to any comments received from the Commission with respect to the Shelf
Registration Statement, or any amendment, post-effective amendment or supplement
relating thereto; and (iv) comply with the provisions of the Securities Act with
respect to the disposition of all securities covered by the Shelf Registration
Statement during the applicable period in accordance with the intended method or
methods of distribution by the selling Holders thereof. Notwithstanding anything
to the contrary contained herein, the Company shall not be required to take any
of the actions described in clauses (i), (ii) or (iii) above with respect to
each particular Holder of Registrable Securities unless and until the Company
has received either a written notice (a "Registration Notice") from a Holder
that such Holder intends to make offers or sales under the Shelf Registration
Statement as specified in such Registration Notice or a written response from
such Holder of the type contemplated by Section 2(b); provided, however, that
the Company shall have 7 business days to prepare and file any such amendment or
supplement after receipt of a Registration Notice. Once a Holder has delivered
such a written response or a Registration Notice to the Company, such Holder
shall promptly provide to the Company such information as the Company reasonably
requests in order to identify such Holder and the method of distribution in a
post-effective amendment to the Shelf Registration Statement or a supplement to
a Prospectus. Unless otherwise approved in writing by the Company in its sole
discretion, offers or sales under the Shelf Registration Statement may be made
only during a Sale Period. Such Holder also shall notify the Company in writing
upon completion of such offer or sale or at such time as such Holder no longer
intends to make offers or sales under the Shelf Registration Statement.

               (c) furnish to each Holder of Registrable Securities that has
delivered a Registration Notice to the Company, without charge, as many copies
of each applicable 



                                      -4-

Prospectus, including each preliminary Prospectus, and any amendment or
supplement thereto and such other documents as such Holder may reasonably
request, in order to facilitate the public sale or other disposition of the
Registrable Securities; the Company consents to the use of such Prospectus,
including each preliminary Prospectus, by each such Holder of Registrable
Securities in connection with the offering and sale of the Registrable
Securities covered by such Prospectus or the preliminary Prospectus.

               (d) use its reasonable best efforts to register or qualify the
Registrable Securities by the time the Shelf Registration Statement is declared
effective by the SEC under all applicable state securities or "blue sky" laws of
such jurisdictions as any Holder of Registrable Securities covered by the Shelf
Registration Statement shall reasonably request in writing, keep each such
registration or qualification effective during the period the Shelf Registration
Statement is required to be kept effective or during the period offers or sales
are being made by a Holder that has delivered a Registration Notice to the
Company, whichever is shorter, and do any and all other acts and things may be
reasonably necessary or advisable to enable such Holder to consummate the
disposition in each such jurisdiction of such Registrable Securities owned by
such Holder, provided, however, that the Company not be required (i) to qualify
generally to do business in any jurisdiction or to register as a broker or
dealer in such jurisdiction where it would not be required so to qualify or
register but for this Section 3(d), (ii) to subject itself to taxation in any
such jurisdiction or (iii) to submit to the general service of process in any
such jurisdiction.

               (e) notify each Holder when the shelf Registration Statement has
become effective and notify each Holder that has delivered a Registration Notice
to the Company promptly and, if requested by such Holder, confirm such advice in
writing (i) when any post-effective amendments and supplements to the Shelf
Registration Statement become effective, (ii) of the issuance by the Commission
or any state securities authority of any stop order suspending the effectiveness
of the Shelf Registration Statement or the initiation of any proceedings for
that purpose, (iii) if the Company receives any notification with respect to the
suspension of the qualification of the Registrable Securities for sale in any
jurisdiction or the initiation of any proceeding for such purpose and (iv) of
the happening of any event during the period the Shelf Registration Statement is
effective as a result of which the Shelf Registration Statement or a related
Prospectus contains any untrue statement of a material fact or omits to state
any material fact required to be stated therein or necessary to make the
statements therein (in the case of the Prospectus, in light of the circumstances
under which they were made) not misleading.

               (f) make every reasonable effort to obtain the withdrawal of any
order suspending the effectiveness of the Shelf Registration Statement at the
carried possible moment.

               (g) furnish to each Holder that has delivered a Registration
Notice to the Company, without charge, at least one conformed copy of the Shelf
Registration Statement and any post-effective amendment thereto (without
documents incorporated therein by reference or exhibits thereto, unless
requested).

               (h) cooperate with the selling Holders to facilitate the timely
preparation and delivery of certificates representing Registrable Securities to
be sold and not bearing any Securities Act legend; and enable certificates for
such Registrable Securities to be issued for 



                                      -5-

such numbers of shares and registered in such names as the selling Holders may
reasonably request at least two business days prior to any sale of Registrable
Securities.

               (i) subject to the last three sentences of Section 3(b) hereof,
upon the occurrence of any event contemplated by Section 3(e)(iv) hereof, use
its reasonable best efforts promptly to prepare and file a supplement or
prepare, file and obtain effectiveness of a post-effective amendment to the
Shelf Registration Statement or a related Prospectus or any document
incorporated therein by reference or file any other required document so that,
as thereafter delivered to the purchasers of the Registrable Securities, such
Prospectus will not contain any untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein, in the light of the circumstances under which they were
made, not misleading.

               (j) make available for inspection by representatives of the
selling Holders and any counsel or accountant retained by such Holders, all
financial and other records, pertinent corporate documents and properties of the
Company, and cause the respective officers, directors and employees of the
Company to supply all information reasonably requested by any such
representative, counsel or accountant in connection with the Shelf Registration
Statement; provided, however, that such records, documents or information which
the Company determines in good faith to be confidential and notifies such
representatives, counsel or accountants in writing that such records, documents
or information are confidential, shall not be disclosed by the representatives,
counsel or accountants unless (i) the disclosure of such records, documents or
information is necessary to avoid or correct a material misstatement or omission
in the Shelf Registration Statement, (ii) the release of such records, documents
or information is ordered pursuant to a subpoena or outer order from a court of
competent jurisdiction or (iii) such records, documents or information have been
generally made available to the public otherwise than in violation of this
Agreement.

               (k) within a reasonable time prior to the filing of any
Prospectus, any amendment to the Shelf Registration Statement or amendment or
supplement to a Prospectus, provide copies of such document (not including any
documents incorporated by reference therein unless requested) to the Holders of
Registrable Securities that have provided a Registration Notice to the Company.

               (l) use its reasonable best efforts to cause all Registrable
Securities to be listed on any securities exchange on which similar securities
issued by the Company are then listed.

               (m) obtain a CUSIP number for all Registrable Securities, not
later than the effective date of the Shelf Registration Statement.

               (n) otherwise use its reasonable efforts to comply with all
applicable rules and regulations of the Commission and make available to its
security holders, as soon as reasonably practicable, an earnings statement
covering at least 12 months which shall satisfy the provisions of Section 11(a)
of the Securities Act and Rule 158 thereunder.

               (o) use its reasonable best efforts to cause the Registrable
Securities covered by the Shelf Registration Statement to be registered with or
approved by such other governmental agencies or authorities as may be necessary
by virtue of the business and 



                                      -6-

operations of the Company to enable Holders that have delivered Registration
Notices to the Company to consummate the disposition of such Registrable
Securities.

                  The Company may require each Holder to furnish to the Company
in writing such information regarding the proposed distribution by such Holder
of such Registrable Securities as the Company may from time to time reasonably
request in writing.

                  In connection with and as a condition to the Company's
obligations with respect to the Shelf Registration Statement pursuant to Section
2 hereof and this Section 3, each Holder agrees that (i) it will not offer or
sell its Registrable Securities under the Shelf Registration Statement until (A)
it has either (1) provided a Registration Notice pursuant to Section 3(b) hereof
or (2) had Registrable Securities included in the Shelf Registration Statement
at the time it became effective pursuant to Section 2(b) hereof and (B) it has
received copies of the supplemented or amended Prospectus contemplated by
Section 3(b) hereof and receives notice that any required post-effective
amendment has become effective; (ii) upon receipt of any notice from the Company
of the happening of any event of the kind described in Section 3(e)(iv) hereof,
such Holder will forthwith discontinue disposition of Registrable Securities
pursuant to the Shelf Registration Statement until such Holder receives copies
of the supplemented or amended Prospectus contemplated by Section 3(i) hereof
and receives notice that any post-effective amendment has become effective, and,
if so directed by the Company, such Holder will deliver to the Company (at the
expense of the Company) all copies in its possession, other than permanent file
copies then in such Holder's possession, of the Prospectus covering such
registrable Securities current at the time of receipt of such notice; and (iii)
all offers and sales under the Shelf Registration Statement shall be completed
during the first available Sale Period when offers or sales can be made pursuant
to clause (i) above, and upon expiration of such Sale Period the Holder will not
offer or sell its Registrable Securities under the Shelf Registration Statement
until it has again complied with the provisions of clauses (i)(A)(1) and (B)
above, provided, however, that if the entirety of a Sale Period is for any
reason not available to the Holder, the Holder shall also be entitled to make
offers and sales during the next succeeding Sale Period.


         SECTION 4. PIGGYBACK REGISTRATION.

               (a) Whenever (x) the Company proposes to register any shares of
its Common Stock (or securities convertible into or exchangeable or exercisable
for such Common Stock) under the Securities Act for its own account or the
account of any shareholder of the Company (other than offerings pursuant to
employee plans, or non-cash offerings in connection with a proposed acquisition,
exchange offer, recapitalization or similar transaction), and (y) the
registration form otherwise to be used by the Company may be used for the
registration of Registrable Securities (a "Piggyback Registration"), the Company
will give prompt written notice to all Holders of its intention to effect such a
registration and will, subject to Section 4(b) and Section 10 hereof, include in
such registration all Registrable Securities with respect to which such Holders
request in writing to be so included within 20 days after the receipt of the
Company's notice.

               (b) If a registration pursuant to this Section 4 involves an
underwritten offering and the managing underwriter advises the Company in good
faith that in its opinion the number of securities requested to be included in
such registration exceeds the number which can be sold in such offering without
having an adverse effect on such offering, including the 



                                      -7-

price at which such securities can be sold, then the Company will be required to
include in such registration the maximum number of shares that such underwriter
advises can be so sold, allocated (x) first, to the securities the Company
proposes to sell, (y) second, among the shares of Common Stock requested to be
included in such registration by the Holders, considered in the aggregate (if
such registration was initiated by the Company), and any other shareholder of
the Company with shares of Common Stock eligible for registration, pro rata, on
the basis of the number of shares of Common Stock such holder requests be
included in such registration, and (z) third, among other securities, if any,
requested and otherwise eligible to be included in such registration.

               (c) Nothing contained herein shall prohibit the Company from
determining, at any time, not to file a registration statement or, if filed, to
withdraw such registration or terminate or abandon the registration related
thereto.


         SECTION 5. REQUESTED REGISTRATION.

               (a) RIGHT TO REQUEST REGISTRATION. Upon the written request of
Holders owning 10% or more of the outstanding Registrable Securities then owned
in the aggregate by such Holders (the "Requesting Holders') (computed for these
purposes as if all outstanding shares of Preferred Stock and all shares of
Preferred Stock thereafter issuable pursuant to the Development Agreements have
been converted into shares of Common Stock), requesting that the Company effect
the registration under the Securities Act of at least the Minimum Registration
Amount, the Company shall use its best efforts to effect, as expeditiously as
possible, following the prompt (but in no event later than 15 days following the
receipt of such written request) delivery of notice to all Holders, the
registration under the Securities Act of such number of shares of Registrable
Securities owned by the Requesting Holders and requested by the Requesting
Holders to be so registered (subject to Section 5(c) hereof), together with (x)
all other shares of Common Stock entitled to registration, and (y) securities of
the Company which the Company elects to register and offer for its own account,
provided, however, that the Company shall not be required to (i) subject to
Section 5(b) below, effect more than a total of three such registrations
pursuant to this Agreement or (ii) file a registration statement relating to a
registration request pursuant hereto within a period of six months after the
effective date of any other registration statement of the Company requested
hereunder (other than pursuant to Section 2) or pursuant to which the Requesting
Holders shall have been given an opportunity to participate pursuant to Section
4 hereof and which opportunity they declined or which registration statement
under Section 4 hereof included shares of Registrable Securities (so long as
such registration statement became and was effective for sufficient time to
permit the sales contemplated thereby); provided, further, that the Company
shall not be required to file a registration statement relating to an offering
of Common Stock on a delayed or continuous basis pursuant to Rule 415 (or any
successor to similar effect) promulgated under the Securities Act if the Company
is not, at the time, eligible to register shares of Common Stock on form S-3 (or
a successor form).


         Notwithstanding the foregoing, if the Board of Directors of the Company
determines in its good faith judgment, (x) after consultation with a nationally
recognized investment banking firm, that there will be an adverse effect on a
then contemplated public offering of the Company's securities, (y) that the
disclosures that would be required to be made by the Company in 



                                      -8-

connection with such registration would be materially harmful to the Company
because of transactions then being considered by, or other events then
concerning the Company, or (z) the registration at the time would require the
inclusion of pro forma or other information, which requirements the Company is
reasonably unable to comply with, then the Company may defer the filing (but not
the preparation) of the registration statement which is required to effect any
registration pursuant to this Section 5 for a reasonable period of time, but not
in excess of 90 calendar days (or any longer period agreed to by the Holders),
provided that at all times the Company is in good faith using all reasonable
efforts to file such registration statement as soon as practicable.

               (b) EFFECTIVE REGISTRATION. A registration requested pursuant to
this Section 5 shall not be deemed to have been effected (and, therefore, not
requested for purposes of Section 5(a) above) (w) unless the registration
statement relating thereto has become effective under the Securities Act, (x) if
after it has become effective such registration is interfered with by any stop
order, injunction or other order or requirement of the Commission or other
governmental agency or court for any reason other than a misrepresentation or an
omission by a Holder and, as a result thereof, the shares of Registrable
Securities requested to be registered cannot be completely distributed in
accordance with the plan of distribution, (y) if the conditions to closing
specified in the purchase agreement or underwriting agreement entered into in
connection with such registration are not satisfied or waived other than by
reason of some act or omission by a participating Holder or (z) if with respect
to what would otherwise be deemed the third, or last, request under Section 5(a)
hereof, less than all of the shares of Common Stock that the Holders requested
be registered were actually registered due to the operation of Section 5(c)
hereof, provided that clause (z) above may not be invoked by the Holders unless
(I) such request includes at least the Minimum Registrable Amount, or (II) if
such request includes an amount that is less than the Minimum Registrable
Amount, Rule 144 under the Securities Act is not available to the Holders for
the sale in any three (3) month period of all of the shares of Common Stock
owned by the Holders; and provided further that clause (z) above may be invoked
only at the request of Holders meeting the foregoing requirements and owning
more than 10% of the shares of Registrable Securities then owned (computed as
aforesaid) in the aggregate by the Holders.

               (c) PRIORITY. If a requested registration pursuant to this
Section 5 involves an underwritten offering and the managing underwriter shall
advise the Company that in its opinion the number of securities requested to be
included in such registration exceeds the number which can be sold in such
offering without having an adverse effect on such offering, including the price
at which such securities can be sold, then the Company will be required to
include in such registration the maximum number of shares that such underwriter
advises can be so sold, allocated (x) first, among all shares of Common Stock
requested by Holders to be included in such registration, pro rata on the basis
of the number of shares of Common Stock then owned by each of them (or, if such
holder requests that less than all of the shares of Common Stock owned by such
holder be included in such registration such lesser number of shares) (y)
second, to any securities requested to be included in such registration by any
other shareholder of the Company having registration rights and (z) third, to
any securities the Company proposes to sell.


                                      -9-

         SECTION 6. REGISTRATION PROCEDURES.

         If and whenever the Company is required to use its best efforts to
effect or cause the registration of any Registrable Securities under the
Securities Act as provided in this Agreement pursuant to Section 4 or 5 hereof,
the Company shall:

               (a) prepare and file with the Commission as expeditiously as
possible but in no event later than 90 days after receipt of a request for
registration with respect to such Registrable Shares, a registration statement
on any form for which the Company then qualifies or which counsel for the
Company shall deem appropriate, which form shall be available for the sale of
the Registrable Securities in accordance with the intended methods of
distribution thereof, and use its best efforts to cause such registration
statement to become effective; provided that before filing with the Commission a
registration statement or prospectus or any amendments or supplements thereto,
including documents incorporated by reference after the initial filing of any
registration statement, the Company shall (x) furnish to each participating
Holder and to one firm of attorneys selected collectively by the participating
Holders and the holders of other securities covered by such registration
statement, but in no event to more than one such counsel for all such selling
securityholders, copies of all such documents proposed to be filed, which
documents shall be subject to the review of the participating Holders and such
counsel, and (y) notify the participating Holders of any stop order issued or
threatened by the Commission and take all reasonable actions required to prevent
the entry of such stop order or to remove it if entered;

               (b) prepare and file with the Commission such amendments and
supplements to such registration statement and the prospectus used in connection
therewith as may be necessary to keep such registration statement effective for
a period of not less than 180 days or such shorter period which shall terminate
when all Registrable Securities covered by such registration statement have been
sold (but not before the expiration of the 90-day period referred to in Section
4(3) of the Securities Act and Rule 174 thereunder, or any successor thereto, if
applicable), and comply with the provisions of the Securities Act with respect
to the disposition of all securities covered by such registration statement
during such period in accordance with the intended methods of disposition by the
sellers thereof set forth in such registration statement;

               (c) furnish, without charge, to the participating Holders and
each underwriter, if any, such number of copies of such registration statement,
each amendment and supplement thereto (including one conformed copy to each
participating Holder and one signed copy to each managing underwriter and in
each case including all exhibits thereto), and the prospectus included in such
registration statement (including each preliminary prospectus), in conformity
with the requirements of the Securities Act, and such other documents as the
participating Holders may reasonably request in order to facilitate the
disposition of the Registrable Securities registered thereunder;

               (d) use its best efforts to register or qualify such Registrable
Securities covered by such registration statement under such other securities or
blue sky laws of such jurisdiction as the participating Holders, and the
managing underwriter, if any, reasonably requests and do any and all other acts
and things which may be reasonable necessary or advisable to enable the
participating Holders and each underwriter, if any to consummate the disposition
in such jurisdiction of the Registrable Securities registered thereunder,
provided that 



                                      -10-

the Company shall not be required to (x) qualify generally to do business in any
jurisdiction where it would not otherwise be required to quality but for this
Section 6(d), (y) subject itself to taxation in any such jurisdiction or (z)
consent to general service of process in any such jurisdiction;

               (e) immediately notify the managing underwriter, if any, and the
Holders at any time when a prospectus relating thereto is required to be
delivered under the Securities Act, of the happening of any event which comes to
the Company's attention if as a result of such event the prospectus included in
such registration statement contains an untrue statement of a material fact or
omits to state any material fact required to be stated therein or necessary to
make the statements therein not misleading, and the Company shall promptly
prepare and furnish to the participating Holders and any other holder of
securities covered by such registration statement and prospectus a supplement or
amendment to such prospectus so that as thereafter delivered, such prospectus
shall not contain an untrue statement of a material fact or omit to state any
material fact required to be stated therein or necessary to make the statements
therein not misleading; provided, however. that if the Company determines in
good faith that the disclosure that would be required to be made by the Company
would be materially harmful to the Company because of transactions then being
considered by, or other events then concerning, the Company, or a supplement or
amendment to such prospectus at such time would require the inclusion of pro
forma or other information, which requirement the Company is reasonably unable
to comply with, then the Company may defer for a reasonable period of time, not
to exceed 90 days, furnishing to the participating Holders and any other holder
of securities covered by such registration statement and prospectus a supplement
or amendment to such prospectus, provided, further, that at all times the
Company is in good faith using all reasonable efforts to file such amendment as
soon as practicable;

               (f) use its best efforts to cause all such securities being
registered to be listed on each securities exchange on which similar securities
issued by the Company are then listed, and enter into such customary agreements
including a listing. application and indemnification agreement in customary form
(provided that the applicable listing requirements are satisfied), and to
provide a transfer agent and register for such Registrable Shares covered by
such registration statement no later than the effective date of such
registration statement;

               (g) make available for inspection by any of the participating
Holders and any holder of securities covered by such registration statement, any
underwriter participating in any distribution pursuant to such registration
statement, and any attorney, accountant or other agent retained by such persons
(collectively, the "Inspectors"), all financial and other records of the Company
and its subsidiaries (collectively, 'Records'), if any, as shall be reasonably
necessary to enable them to exercise their due diligence responsibility, and
cause the Company's and its subsidiaries' officers, directors and employees to
supply all information and respond to all inquiries reasonably requested by any
such Inspector in connection with such registration statement. Notwithstanding
the foregoing, the Company shall have no obligation to disclose any Records to
the Inspector in the event the Company determines that such disclosure is
reasonably likely to have an adverse effect on the Company's ability to asset
the existence of an attorney-client privilege with respect thereto;

               (h) if requested use its best efforts to obtain a "cold comfort"
letter and a "bring-down cold comfort" letter from the Company's independent
public accountants in customary form and covering such matters of the type
customarily covered by such letters;

                                      -11-

               (i) enter into a form of underwriting agreement that contains
customary terms and provisions for similar securities offerings;

               (j) make available senior management personnel to participate in.
and cause them to cooperate with the underwriters in connection with. "road
show" and other customary marketing activities, including "one-on-one" meetings
with prospective purchasers of the Registrable Securities; and

               (k) otherwise use its best efforts to comply with all applicable
rules and regulations of the Commission, and make available to its security
holders. as soon as reasonably practicable. an earning statement covering a
period of at least 12 months, beginning with the first: month after the
effective date of the registration statement (as the term "effective date" is
defined in Rule 158(c) under the Securities Act), which earning statement shall
satisfy the provisions of Section 11(a) of the Securities Act and Rule 158
thereunder.

         It shall be a condition precedent to the obligation of the Company to
take any action pursuant to this Agreement in respect of Registrable Securities
which are to be registered at the request of any of the participating Holders
that the participating Holders shall furnish to the Company such information
regarding the securities held by the participating Holders and the intended
method of disposition thereof as the Company shall reasonably request and as
shall be required in correction with the action taken by the Company.

         Each of the Holders agrees that, upon receipt of any notice from the
Company of the happening of any event of the kind described in Section 6(e)
hereof, the Holders shall discontinue disposition of Registrable Shares pursuant
to the registration statement covering such Registrable Securities until receipt
of the copies of the supplemented or amended prospectus contemplated by Section
6(c) hereof or until otherwise notified by the Company, and, if so directed by
the Company, the participating Holders shall deliver to the Company (at the
Company's expense) all copies (including, without limitation, any and all
drafts), other than permanent file copies, then in any participating Holder's
possession, of the prospectus coveting such Registrable Securities at the time
of receipt of such notice. In the event the Company shall give any such notice,
the period specified in Section 6(b) hereof shall be extended by the greater of
(x) three months and (y) the number of days during the period from and including
the date of the giving of such notice pursuant to Section 6(e) hereof to and
including the date when each of the participating Holders shall have received
the copies of the supplemented or amended prospectus contemplated by Section
6(e) hereof.

         SECTION 7. SELECTION OF UNDERWRITERS.

         If any offering pursuant to a registration statement is to be an
underwritten offering, the Company will select a managing underwriter or
underwriters to administer the offering; provided that in the case of a
registration statement pursuant to Section 5 hereof, the Holders holding more
than 50% of the shares of Registrable Securities held by the Holders to be
included in such underwritten offering shall select the managing underwriter or
underwriters, subject to the consent of the Company which shall not be
unreasonably withheld.


                                      -12-


         SECTION 8. REGISTRATION EXPENSES.

         The Company shall pay, in connection with any registration pursuant to
Section 2. 4 or 5, the following registration expenses incurred in connection
therewith: (i) all Commission, stock exchange or NASD registration and filing
fees, (ii) all fees and expenses. of compliance with securities or blue sky laws
(including reasonable fees and disbursements of counsel in connection with the
blue sky qualifications of the Registrable Securities), (iii) printing expenses,
(iv) internal expenses (including without limitation, all salaries and expenses
of its officers and employees performing legal or accounting duties), (v) the
fees and expenses incurred in connection with the listing of the Registrable
Securities on any national securities exchange or interdealer quotation system,
(vi) the reasonable fees and disbursements of counsel for the Company and
customary fees and expenses for independent certified public accountants
retained by the Company (including the expenses of any comfort letters or costs
associated with the delivery by independent certified public accountants of a
comfort letter or comfort letters), (vii) the reasonable fees and disbursements
of not more than one firm of attorneys acting as legal counsel for (x) all of
the selling shareholders, collectively, in respect of a registration pursuant to
Section 2 hereof or (y) all of the participating Holders, collectively, in
respect of a registration pursuant to Sections 4 or 5 hereof, (viii) the fees
and expenses of any registrar and transfer agent for the Common Stock, (ix) the
underwriting fees, discounts and commissions applicable to any shares of Common
Stock sold for the account of the Company and (x) all expenses of any Person in
preparing or assisting in preparing, word processing, printing and distributing
any registration statement, prospectus, certificates and other documents
relating to the performance of and compliance with this Agreement. Except as
otherwise provided in clause (ix) of this Section 8, the Company shall have no
obligation to pay any underwriting fees, discounts or commissions attributable
to the sale of Registrable Shares.


         SECTION 9. INDEMNIFICATION; CONTRIBUTION.

               (a) The Company agrees to indemnify and hold harmless each seller
of Registrable Securities covered by a Registration Statement filed pursuant to
this Agreement, and such seller's partners, directors, officers, employees and
any Person who controls such seller under the Securities Act (each, an
"Indemnitee") from and against any and all losses, claims, damages, liabilities
and expenses (including reasonable costs of investigation) arising out of or
based upon any untrue statement or alleged untrue statement of a material fact
contained in any prepricing prospectus, registration statement or prospectus or
in any amendment or supplement thereto, or arising out of or based upon any
omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading,
except insofar as such losses, claims, damages, liabilities or expenses rise out
of or are based upon any untrue statement or omission or alleged untrue
statement or omission which has been made therein or omitted therefrom in
reliance upon and in conformity with the information relating to a participating
Holder furnished in writing to the Company by or on behalf of a participating
Holder expressly for use in connection therewith. The foregoing indemnity
agreement shall be in addition to any liability which the Company may otherwise
have.

               (b) If any action, suit or proceeding shall be brought against an
Indemnitee in respect of which indemnity may be sought against the Company, such
Indemnitee shall promptly notify the Company, and the Company shall assume the
defense thereof, including the 



                                      -13-

employment of counsel and payment of all fees and expenses. The Indemnitee shall
have the right to employ separate counsel in any such action, suit or proceeding
and to participate in the defense thereof, but the fees and expenses of such
counsel shall be at the expense of such Indemnitee unless (x) the Company has
agreed in writing to pay such fees and expenses, (y) the Company has failed to
assume the defense and employ counsel, or (z) the named parties to any such
action, suit or proceeding (including any impleaded parties) include both such
Indemnitee and the Company, and such Indemnitee shall have been advised by its
counsel that representation of such Indemnitee and the Company by the same
counsel would be inappropriate under applicable standards of professional
conduct (whether or not such representation by the same counsel has been
proposed) due to actual or potential differing interests between them (in which
case the Company shall not have the right to assume the defense of such action,
suit or proceeding on behalf of such Indemnitee). It is understood, however,
that the Company shall, in connection with any one such action, suit or
proceeding or separate but substantially similar or related actions, suits or
proceedings in the same jurisdiction arising out of the same general allegations
or circumstances, be liable for the reasonable fees and expenses of only one
separate firm of attorneys (in addition to any local counsel) at any time for
all such Indemnitees not having actual or potential differing interests among
themselves, and that all such fees and expenses shall be reimbursed as they are
incurred. The Company shall not be liable for any settlement of any such action,
suit or proceeding effected without its written consent, but if settled with
such written consent, or if them be a final judgment for the plaintiff in any
such action, suit or proceeding, the Company agrees to indemnify and hold
harmless such Indemnitee, to the extent provided in the preceding paragraph,
from and against any loss, claim, damage, liability or expense by reason of such
settlement or judgment.

               (c) Each of the participating Holders, severally and not jointly,
agree to indemnify and hold harmless the Company, its directors, its officers
who sign the registration statement, and any person who controls the Company
within the meaning of Section 15 of the Securities Act or Section 20 of the
Exchange Act, to the same extent as the foregoing indemnity from the Company to
an Indemnitee, but only with respect to information relating to such Holder
furnished in writing by or on behalf of such Holder expressly for use in the
registration statement, prospectus or any prepricing prospectus, or any
amendment or supplement thereto. If any action, suit or proceeding shall be
brought against the Company, any of its directors, any such officer, or any such
controlling person based on the registration statement, prospectus or any
prepricing prospectus, or any amendment or supplement thereto, and in respect of
which indemnity may be sought against any Holder pursuant to this Section 9(c),
such Holder shall have the rights and duties given to the Company by Section
9(b) hereof (except that if the Company shall have assumed the defense thereof
such Holder shall not be required to do so, but may employ separate counsel
therein and participate in the defense thereof, but the fees and expenses of
such counsel shall be at the Holder's expense), and the Company, its directors,
any such officer, and any such controlling person shall have the rights and
duties given to an Indemnitee by Section 9(b) hereof. The foregoing indemnity
agreement shall be in addition to any liability which the participating Holders
may otherwise have.

               (d) If the indemnification provided for in this Section 9 is
unavailable to an indemnified party under paragraphs (a) or (c) hereof in
respect of any losses, claims, damages, liabilities or expenses referred to
therein, then an indemnifying party, in lieu of indemnifying such indemnified
party, shall contribute to the amount paid or payable by such indemnified party
as a result of such losses, claims, damages, liabilities or expenses in such
proportion as is appropriate to reflect the relative fault of the Company and of
the participating Holders in 



                                      -14-

connection with the statements or omissions that resulted in such losses,
claims, damages, liabilities or expenses. The relative fault of the Company on
the one hand and a participating Holder on the other hand shall be determined by
reference to, among other things, whether the untrue or alleged untrue statement
of a material fact or the omission or alleged -omission to state a material fact
relates to information supplied by the Company on the one hand or by such
participating Holder on the other hand and the parties' relative intent,
knowledge, access or information and opportunity to correct or prevent such
statement or omission.

               (e) The Company and the participating Holders agree that it would
not be just and equitable if contribution pursuant to this Section 9 were
determined by a pro rata allocation or by any other method of allocation that
does not take account of the equitable considerations referred to in Section
9(d) hereof. The amount paid or payable by an indemnified party as a result of
the losses, claims, damages, liabilities and expenses referred to in Section
9(d) hereof shall be deemed to include, subject to the limitations set forth
above, any legal or other expenses reasonably incurred by such indemnified party
in connection with investigating any claim or defending any such action, suit or
proceeding. Notwithstanding the provisions of this Section 9, no participating
Holder shall be required to contribute any amount in excess of the amount by
which the proceeds to such participating Holder exceeds the amount of any
damages which such participating Holder has otherwise been required to pay by
reason of such untrue or alleged untrue statement or omission or alleged
omission. No person guilty of fraudulent misrepresentation (within the meaning
of Section 11(f) of the Securities Act) shall be entitled to contribution from
any person who was not guilty of such fraudulent misrepresentation.

               (f) No indemnifying party shall, without the prior written
consent of the indemnified party, effect any settlement of any pending or
threatened action, suit or proceeding in respect of which any indemnified party
is or could have been a party and indemnity could have been sought hereunder by
such indemnified party, unless such settlement includes an-unconditional release
of such indemnified party from all liability on claims that are the subject
matter of such action, suit or proceeding.

               (g) Any losses, claims, damages, liabilities or expenses for
which an indemnified parry is entitled to indemnification or contribution under
this Section 9 shall be paid by the indemnifying party to the indemnified party
as such losses, claims, damages, liabilities or expenses are incurred. The
indemnity and contribution agreements contained in this Section 9 shall remain
operative and in full force and effect, regardless of (i) any investigation made
by or on behalf of an Indemnitee, the Company, its directors or officers, or any
person controlling the Company, and (ii) any termination of this Agreement.


         SECTION 10. PARTICIPATION IN UNDERWRITTEN REGISTRATIONS.

         A Holder may not participate in any underwritten offering pursuant to
Section 4 or 5 hereof unless such Holder (i) agrees to sell its Registrable
Securities on the basis provided in any underwriting arrangements which, to the
extent applicable solely to the participating Holders, are approved by the
participating Holders in their reasonable discretion or which, to the extent
applicable to the Company and the participating Holders, are approved by the
Company in its reasonable discretion and (ii) completes and executes all
questionnaires, powers of attorney, indemnities, underwriting agreements and
other documents (including lock-



                                      -15-

up agreements) reasonably required under the terms of such underwriting
arrangements which are not in consistent with the terms of this Agreement.



         SECTION 11. OTHER REGISTRATION RIGHTS.

         The Company agrees that it shall not enter into any agreement which
provides registration rights to any Person that are inconsistent with the
provisions contained in this Agreement. If the Company does become a party to
such an agreement, the Company agrees that to the extent that the provisions of
such agreement conflict with this Agreement, the provisions of this Agreement
shall control.

         SECTION 12. RULE 144 SALES.

               (a) The Company covenants that it will file the reports required
to be filed by the Company under the Securities Act and the Exchange Act, so as
to enable any Holder to sell Registrable Securities pursuant to Rule 144 under
the Securities Act.

               (b) In connection with any sale, transfer or other disposition by
any Holder of any Registrable Securities pursuant to Rule 144 under the
Securities Act, the Company shall cooperate with such Holder to facilitate the
timely preparation and delivery of certificates representing Registrable
Securities to be sold and not bearing any Securities Act legend, and enable
certificates for such Registrable Securities to be for such number of shares and
registered in such names as the selling Holders may reasonably request at least
two business days prior to any sale of Registrable Securities.


         SECTION 13. MISCELLANEOUS.

               (a) AMENDMENTS AND WAIVERS. The provisions of this Agreement,
including the provisions of this sentence, may not be amended, modified or
supplemented, and waivers or consents to departures from the provisions hereto
may not be given without the written consent of the Company and Holders
constituting Majority Holders; provided, however, that no amendment,
modification or supplement or waiver or consent to the departure with respect to
the provisions of Sections 1 through 12, inclusive, hereof or which would impair
the rights of any Holder under such provisions, shall be effective as against
any Holder. Notice of any amendment, modification or supplement to this
Agreement adopted in accordance with this Section 13(a) shall be provided by
Company to each Holder at least thirty (30) days prior to the effective date of
such amendment, modification or supplement.

               (b) NOTICES. All notices and other communications provided for or
permitted hereunder shall be made in writing by hand delivery, registered
first-class mail, telex, telecopier or any courier guaranteeing overnight
delivery, (i) if to a Holder, at the most current address given by such Holder
to the Company by of a notice given in accordance with the provisions of this
Section 13(b), which address initially is, with respect to each Holder, the
address set forth in the Contribution Agreement, the Asset Contribution
Agreement or the Development Agreements, or (ii) if to the Company, at One Logan
Square, Suite 1105, Philadelphia, PA 19103.

                                      -16-

         All such notices and communications shall be deemed to have been duly
given: at the time delivered by hand, if personally delivered; five business
days after being deposited in the mail, postage prepaid, if mailed: when
answered back, if telexed; when receipt is acknowledged, if telecopied; or at
the time delivered if delivered by an air courier guaranteeing overnight
delivery.

               (c) SUCCESSORS AND ASSIGNS. This Agreement shall inure to the
benefit of and be binding upon the successors, assigns and transferees of each
of the Company and the Holders, including without limitation and without the
need for an express assignment, subsequent Holders. If any successor, assignee
or transferee of any Holder shall acquire Registrable Securities, in any manner,
whether by operation of law or otherwise, such Registrable Securities shall be
held subject to all of the terms of this Agreement, and by taking and holding
such Registrable Securities such Person shall be entitled to receive the
benefits hereof and shall be conclusively deemed to have agreed to be bound by
all of the terms and provisions hereof.

               (d) HEADINGS. The headings in this Agreement are for the
convenience of reference only and shall not limit or otherwise affect the
meaning hereof.

               (e) GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF DELAWARE WITHOUT GIVING
EFFECT TO THE CONFLICTS OF LAW PROVISIONS THEREOF.

               (f) SPECIFIC PERFORMANCE. The Company and the Holders acknowledge
that there would be no adequate remedy at law if any party fails to perform any
of its obligations hereunder, and accordingly agree that the Company and each
Holder, in addition to any other remedy to which it may be entitled at law or in
equity, shall be entitled to compel specific performance of the obligations of
another under this Agreement in accordance with the terms and conditions of this
Agreement in any court of the United States or any State thereof having
jurisdiction.

               (g) ENTIRE AGREEMENT. This Agreement is intended by the Company
as a final expression of its agreement and is intended to be a complete and
exclusive statement of the agreement and understanding of the Company in respect
of the subject matter contained herein. This Agreement supersedes all prior
agreements and understandings of the Company with respect to such subject
matter.

               (h) Notwithstanding any other provision of this Agreement to the
contrary, the total number of days that the Holders shall be precluded from the
disposition of Registrable Securities under an effective Registration Statement
coupled with the total number of days that the Company may defer the filing of
the registration statement hereunder shall not exceed 180 in any 12-month period
during the first two years from the date of this Agreement, and shall not exceed
120 days in any 12-month period thereafter.


                                      -17-

         IN WITNESS WHEREOF, the Company has executed this Agreement as of the
date first written above.

                                    CORPORATE OFFICE PROPERTIES TRUST


                                    By:  /s/ Clay W. Hamlin, III
                                        --------------------------------------
                                         Clay W. Hamlin, III
                                         President and Chief Executive Officer


                                      -18-