Exhibit 2.5

                                 FIRST AMENDMENT
                                       TO
               AMENDED AND RESTATED LIMITED PARTNERSHIP AGREEMENT
                                       OF
                        CORPORATE OFFICE PROPERTIES, L.P.

         THIS AMENDMENT (the "Amendment") to the Amended and Restated Limited 
Partnership Agreement of Corporate Office Properties, L.P., a Delaware 
limited partnership (the "Partnership") is made and entered into as of 
September 28, 1998, by and among the undersigned parties.

                                    Recitals

         A. The Partnership is a limited partnership organized under the 
Delaware Revised Uniform Limited Partnership Act (the "Act") and governed by 
that certain Amended and Restated Limited Partnership Agreement dated as of 
March 16, 1998 (the "Partnership Agreement").

         B. The sole general partner of the Partnership is Corporate Office 
Properties Trust, a real estate investment trust formed under the laws of the 
State of Maryland (the "General Partner").

         C. The General Partner and the Partnership have entered into that 
certain Contribution Agreement and Service Company Asset Contribution 
Agreement (the "Constellation Agreements") with Constellation Real Estate 
Group, Inc. ("CREG") and certain partnerships and other entities affiliated 
with CREG (collectively, "Constellation"), pursuant to which Constellation 
will contribute certain real property, partnership and membership interests 
in certain entities which hold real property or mortgages secured by real 
property and certain other assets (the "Constellation Assets") to or for the 
benefit of the General Partner, subject to certain liabilities, in exchange 
for the issuance by the General Partner of approximately 6,928,000 Common 
Shares of Beneficial Interest in the General Partner ("REIT Shares") and 
approximately 969,900 Series A Convertible Preferred Shares of Beneficial 
Interest in the General Partner ("Series A Preferred REIT Shares").

         D. As required under Sections 4.2(B) and (C) of the Partnership 
Agreement, the General Partner intends to transfer the Constellation Assets 
(or cause them to be transferred) to or for the benefit of the Partnership in 
exchange for additional Partnership Interests in the Partnership having 
designations, rights and preferences substantially similar to the economic 
rights of the holders of the REIT Shares and Series A Preferred REIT Shares 
issued by the General Partner in exchange for the Constellation Assets.

         E. The parties desire to amend the Partnership Agreement to provide 
for the contribution of the Constellation Assets by the General Partner to 
the Partnership in exchange for additional Partnership Interests in the 
Partnership in accordance with 




Section 4.2(B) of the Partnership Agreement, and for such other matters as 
set forth below. Unless otherwise defined herein, all capitalized terms used 
in this Amendment shall have the same meanings as set forth in the 
Partnership Agreement.

         NOW THEREFORE, in consideration of the foregoing and of the mutual 
premises set forth herein, the parties hereto, intending to be legally bound 
hereby, hereby amend the Partnership Agreement as follows, effective as of 
the date set forth above:

         1.    The foregoing recitals to this Amendment are hereby incorporated
in and made a part of this Amendment.

         2.    Section 1.1 of the Partnership Agreement is amended by amending
and restating the terms "Partnership Unit," "Preferred Limited Partner," 
"Preferred Unit" and "Priority Return Amount" in their entirety and by adding 
the following additional defined terms:

               "Initial Limited Partners: Those Persons initially admitted to
               the Partnership as Limited Partners in connection with the
               contribution of property to the Partnership in accordance with
               the Formation Agreement and the other Contribution Agreements.

               Initial Preferred Unit: One of the Preferred Units previously
               issued or to be issued after the date hereof to the Initial
               Limited Partners of the Partnership in connection with the
               contribution of the Contributed Property in accordance with
               the Contribution Agreements, and any other Preferred Unit
               issued after the date hereof with the same rights and
               preferences.

               Partnership Unit: A fractional, undivided share of the
               Partnership Interests (other than Partnership Interests
               represented by Preferred Units) of all the Partners heretofore
               or hereafter admitted to the Partnership pursuant to Section
               4.1 or 4.2 hereof.

               Preferred Limited Partner: Those Persons listed as such on
               Exhibit 1 attached hereto and made a part hereof, as such
               Exhibit 1 may be amended from time to time, in their capacity
               as limited partners in the Partnership holding Preferred
               Units, including any Person who becomes a Substituted
               Preferred Limited Partner or an Additional Preferred Limited
               Partner in accordance with the terms of this Agreement and
               including the General Partner, but only in its capacity as the
               holder of Preferred Units.

               Preferred Unit: A portion of the Partnership Interest held by
               a Limited Partner or the General Partner that represents a
               unit of preferred interest in the Partnership, including an
               Initial Preferred Unit, a Series A Preferred Unit and a unit
               of any other class or series of preferred interest in the


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               Partnership that may be issued to a Partner in the future in
               accordance with Section 4.2(A) or (B).

               Priority Return Amount: For each Distribution Period, an
               amount equal to (i) for each Partner holding Initial Preferred
               Units, 1.625% times the number of Initial Preferred Units held
               by such Partner times $25.00, (ii) for each Partner holding
               Series A Preferred Units, 1.375% times the number of Series A
               Preferred Units held by such Partner times $25.00 and (iii)
               for each Partner holding a class of Preferred Units issued
               after the date hereof, such amount as determined by the
               General Partner in accordance with Section 4.2(A) or (B),
               whichever is applicable. For all purposes of this Agreement,
               the holders of Initial Preferred Units, the Series A Preferred
               Units and any future classes or series of Preferred Units
               shall be entitled to allocations and distributions with
               respect to Priority Return Amounts on a pari passu basis. In
               the case of any Preferred Units issued during a Distribution
               Period, the Priority Return Amount attributable to such
               Preferred Units for such Distribution Period shall be pro
               rated to reflect the portion of such Distribution Period
               during which such Preferred Units were outstanding.

               Series A Preferred Unit: One of the Preferred Units to be
               issued to the General Partner in connection with the
               contribution of the Constellation Assets to the Partnership by
               the General Partner, and any other Preferred Unit issued after
               the date hereof with the same rights and preferences."

         3.    (a) Upon acquisition of the Constellation Assets from 
Constellation under the Constellation Agreements, the General Partner shall 
contribute the Constellation Assets to the Partnership, provided that certain 
Constellation Assets may, at the direction of the General Partner, be 
conveyed directly to the Partnership or to one or more limited liability 
companies owned and controlled by the Partnership. The Constellation Assets 
shall be accepted subject to existing liabilities, as the same may be 
modified by the General Partner and/or the Partnership.

               (b) Upon the contribution of the Constellation Assets to 
the Partnership by the General Partner, and in accordance with Section 4.2(B) 
of the Partnership Agreement, the Partnership shall issue to the General 
Partner (i) a number of Partnership Units equal to the number of REIT Shares 
issued by the General Partner to Constellation under the Constellation 
Agreements and (ii) a number of Series A Preferred Units equal to the number 
of Series A Preferred REIT Shares issued by the General Partner to 
Constellation under the Constellation Agreements.

               (c) For purposes of the Partnership Agreement, including the
maintenance of Capital Accounts, the General Partner shall be treated as making
a Capital Contribution equal the sum of (i) $10.50 times the number of
Partnership Units issued to the General Partner, plus (ii) $25.00 times the
number of Series A Preferred Units issued 


                                       3



to the General Partner. For purposes of the Partnership Agreement, the 
initial Agreed Value of the Constellation Assets shall equal the sum of the 
foregoing Capital Contribution made by the General Partner plus the aggregate 
amount of liabilities assumed by the Partnership in connection with such 
contribution or to which the Constellation Assets are subject.

               (d) The General Partner shall amend Exhibit 1 to the 
Partnership Agreement to reflect the issuance of additional Partnership Units 
and Series A Preferred Units to the General Partner, and shall also amend 
Exhibit 1 to reflect the different classes of Preferred Stock held by the 
respective Partners.

         4.    (a) That portion of the Constellation Assets acquired by the 
General Partner from Constellation under that certain Service Company Asset 
Contribution Agreement (the "Service Assets") shall, immediately following 
their contribution to the Partnership by the General Partner, be contributed 
by the Partnership to Corporate Office Management, Inc., a Maryland 
corporation ("COMI"), in exchange for cash of $24,750 (or such other amount 
as determined by the General Partner), one or more promissory notes in the 
aggregate principal amount of $2,005,000, 10 shares of Class A Voting Stock 
of COMI and 18,800 shares of Class B Non-Voting Common Stock of COMI.

               (b) The Constellation Assets other than the Service Assets may 
be held directly by the Partnership, or through such partnerships, limited 
liability companies or other entities owned and controlled by the Partnership 
as the General Partner may determine.

         5.    Section 5.2(C) of the Partnership Agreement is amended to add 
the following paragraph thereto:

               "(9) In the event that during any taxable year any Preferred
               Units are converted, pursuant to Section 9.8(A), into
               Partnership Units prior to a distribution having been made
               under Section 5.3(A) of an unpaid Priority Return Amount with
               respect to such Preferred Units, there shall be allocated to
               the Partner who held such converted Preferred Units items of
               loss and deduction in an amount equal to the excess of (a)
               allocations previously made with respect to such converted
               Preferred Units pursuant to Section 5.2(A)(5) over (b) the
               Priority Return Amount previously distributed or remaining to
               distributed with respect to such converted Preferred Units
               pursuant to Sections 5.3(A), 9.8(A) and 9.8(B)."

         6.    Section 5.3(A)(2) of the Partnership Agreement is amended and 
restated to read as follows:

               "(2) Second, there shall be distributed with respect to each
               Partnership Unit an amount equal on a per Unit basis to the
               amount distributed (other than in REIT Shares) by the General
               Partner on its common shares during 


                                       4



               the Fiscal Year (other than a liquidating distribution),
               except that (i) the first distribution paid to a Limited
               Partner with respect to newly issued Partnership Units shall
               be pro rated to reflect the actual portion of the Distribution
               Period for which the distribution is being paid during which
               such Partnership Units were outstanding, and (ii) the first
               distribution made to the General Partner with respect to
               Partnership Units newly issued to the General Partner pursuant
               to Section 4.2(B) hereof shall be pro rated to the same extent
               (if any) by which the first dividends payable on the REIT
               Shares newly issued by the General Partner are subject to
               proration. To the extent practicable, distributions under this
               paragraph shall be made at the same time as the dividend
               distributions made by the General Partner on its REIT Shares."

         7.    Section 9.8(A) of the Partnership Agreement is amended and 
restated to read as follows:

               "(A) (1) Each Limited Partner holding Preferred Shares shall
               have the right, at any time or from time to time, to convert
               on or after October 1, 1999 some or all of its Preferred Units
               into Partnership Units, effective upon January 1, April 1,
               July 1 or October 1 of any year, by providing the General
               Partner with a Conversion Notice not less than 30 days prior
               to the effective date of such conversion. Upon the effective
               date of any such conversion, the Preferred Units which are the
               subject of such conversion shall be converted, without
               necessity of any further action by the General Partner, into
               that number of Partnership Units the Limited Partner is
               entitled to receive on such conversion plus an amount of cash
               equal to the accrued Priority Return Amount in respect of such
               Preferred Units.

                        (2) In the case of Initial Preferred Units, each
               Initial Preferred Unit may be converted into Partnership Units
               on the basis of 3.5714 Partnership Units for each Initial
               Preferred Unit being converted.

                        (3) Other classes of Preferred Units, if any, issued
               to Limited Partners after the date hereof shall be convertible
               into Partnership Units on such terms as may be agreed by the
               Partnership and the holder of such Preferred Units, and the
               right to convert such Preferred Units shall be subject to such
               further restrictions and limitations as may be agreed upon.

                        (4) At such time as any Series A Preferred REIT
               Shares issued by the General Partner are converted into REIT
               Shares by the holder thereof, an equal number of Series A
               Preferred Units held by the General Partner shall
               automatically be converted into a number of Partnership Units
               equal to the number of REIT Shares issued by the General
               Partner upon the conversion of such Series A Preferred REIT
               Shares.


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                        (5) In any case in which the conversion into
               Partnership Units under this Section 9.8(A) would result in
               the issuance of a fractional Partnership Unit, the General
               Partner shall pay the converting Partner cash in lieu of
               issuance of a fractional Partnership Unit, with the value of
               such fractional interest being determined by reference to the
               Unit Value applicable on the date of conversion.

         8. Section 9.8(B) of the Partnership Agreement is amended to add the
following sentence at the end thereof:

               "Notwithstanding anything to the contrary in this Section
               9.8(B) or Section 5.3(A)(1) hereof, in any case in which there
               is an unpaid Priority Return Amount with respect to a Series A
               Preferred Unit that is converted pursuant to Section 9.3(A)
               hereof, the converting Partner shall be entitled to
               distributions (and allocations) under Article V and Section
               10.2 of this Agreement to the same extent and in the same
               amount as the holder of the Series A Preferred REIT Shares
               with respect to which such Series A Preferred Units are being
               converted is entitled to receive dividends from the General
               Partner upon the conversion of such Series A Preferred REIT
               Shares."

         9.    Clause (iii) of Section 11.1(B) of the Partnership 
Agreement, relating to amendments that may be made to the Partnership 
Agreement without the consent of any Limited Partner, shall be amended and 
restated as follows:

               "(iii) reflect the admission, substitution, termination or
               withdrawal of Partners in accordance with this Agreement
               (including the issuance of Partnership Units and Preferred
               Units to a Partner (including the General Partner) in
               accordance with the requirements of Section 4.2(A) or (B)
               hereof, and the designation of the preferences and rights of
               any such Preferred Units),"




               (Remainder of Page Intentionally Left Blank)


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         10.   This Amendment may be executed in several counterparts, which 
shall be treated as originals for all purposes, and all so executed shall 
constitute one amendment, and shall be binding and effective when a 
counterpart of this Amendment has been executed by the General Partner and 
that number of Limited Partners whose consent is required to this Amendment 
under Section 11.1 of the Partnership Agreement.

               IN WITNESS WHEREOF, this Amendment has been duly executed and 
delivered by the parties hereto as of the day and year first above written.


GENERAL PARTNER:

CORPORATE OFFICE PROPERTIES TRUST

By:
   -----------------------------------------


LIMITED PARTNERS:

SHIDLER EQUITIES, L.P.

By:  SHIDLER EQUITIES CORP.

By:  
   -----------------------------------------
      Name:
      Title:



- --------------------------------------------
Jay H. Shidler

LBCW LIMITED PARTNERSHIP


By: /s/ Clay W. Hamlin, III
   -----------------------------------------
   Clay W. Hamlin, III, General Partner

CHLB PARTNERSHIP


By: /s/ Clay W. Hamlin, III
   -----------------------------------------
   Clay W. Hamlin, III, General Partner


                                       7





/s/ Clay W. Hamlin, III
- --------------------------------------------
Clay W. Hamlin, III

LGR INVESTMENT FUND, LTD.


By:
   -----------------------------------------
   Name:



- --------------------------------------------
Robert L. Denton



- --------------------------------------------
John E. de B. Blockey, Trustee of the
    John E. de B. Blockey Living Trust
    dated 9/12/88



- --------------------------------------------
Henry D. Bullock



- --------------------------------------------
Frederick K. Ito


/s/ James K. Davis
- --------------------------------------------
James K. Davis


/s/ Denise J. Liszewski
- --------------------------------------------
Denise J. Liszewski



- --------------------------------------------
Samuel Tang


/s/ David P. Hartsfield
- --------------------------------------------
David P. Hartsfield


                                       8



/s/ Lawrence J. Taff
- --------------------------------------------
Lawrence J. Taff


/s/ Kimberly F. Aquino
- --------------------------------------------
Kimberly F. Aquino

TIGER SOUTH BRUNSWICK, L.L.C.



By:
   -----------------------------------------
    Name:
    Title:

WESTBROOK REAL ESTATE FUND T, L.P.

By:  WESTBROOK REAL ESTATE PARTNERS
       MANAGEMENT T., L.L.C.



By:
   -----------------------------------------
    Name:
    Title:

WESTBROOK REAL ESTATE CO. INVESTMENT
  PARTNERSHIP T., L.P.

By:  WESTBROOK REAL ESTATE PARTNERS
       MANAGEMENT I, L.L.C.



By:
   ------------------------------------------
    Name:
    Title:


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