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                                                                     EXHIBIT 4.2



NUMBER                                                                    SHARES

  A REAL ESTATE INVESTMENT TRUST FORMED UNDER THE LAWS OF THE STATE OF MARYLAND

 SEE REVERSE FOR IMPORTANT NOTICE ON TRANSFER RESTRICTIONS AND OTHER INFORMATION

       THIS CERTIFICATE IS TRANSFERABLE IN MINNEAPOLIS, MN OR NEW YORK, NY

CUSIP  22002T405

                        CORPORATE OFFICE PROPERTIES TRUST


THIS CERTIFIES THAT





IS THE OWNER OF

FULLY PAID AND NONASSESSABLE SERIES F CUMULATIVE REDEEMABLE PREFERRED SHARES OF
BENEFICIAL INTEREST, LIQUIDATION PREFERENCE $25.00 PER SHARE OF Corporate Office
Properties Trust (the "Trust"), transferable on the books of the Trust by the
holder hereof in person or by its duly authorized attorney upon surrender of
this Certificate properly endorsed. This Certificate and the shares represented
hereby are issued and shall be held subject to all of the provisions of the
Declaration Of Trust And Bylaws of the Trust and any amendments thereto. This
Certificate is not valid unless countersigned and registered by the Transfer
Agent and Registrar.

In Witness Whereof, the Trust has caused this Certificate to be executed on its
behalf by its duly authorized officers.

DATED:


TREASURER/SECRETARY                                                    PRESIDENT

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                            [REVERSE OF CERTIFICATE]

                                IMPORTANT NOTICE

     The Trust will furnish to any shareholder, on request and without charge, a
full statement of the information required by Section 8-203(d) of the
Corporations and Associations Article of the Annotated Code of Maryland with
respect to the designations and any preferences, conversion and other rights,
voting powers, restrictions, limitations as to dividends and other
distributions, qualifications, and terms and conditions of redemption of the
shares of each class of beneficial interest which the Trust has authority to
issue and, if the Trust is authorized to issue any preferred or special class in
series, (i) the differences in the relative rights and preferences between the
shares of each series to the extent set, and (ii) the authority of the Board of
Trustees to set such rights and preferences of subsequent series. The foregoing
summary does not purport to be complete and is subject to and qualified in its
entirety by reference to the Declaration of Trust of the Trust, a copy of which
will be sent without charge to each shareholder who so requests. Such request
must be made to the Secretary of the Trust at its principal office or to the
Transfer Agent.

     The shares represented by this Certificate are subject to restrictions on
Beneficial Ownership, Constructive Ownership and Transfer for the purpose of the
Trust's maintenance of its status as a real estate investment trust (a "REIT")
under the Internal Revenue Code of 1986, as amended (the "Code"). Subject to
certain further restrictions and except as expressly provided in the Declaration
of Trust of the Trust, (i) no Person may Beneficially Own or Constructively Own
Common Shares of the Trust in excess of 9.8 percent (in value or number of
shares) of the outstanding Common Shares of the Trust unless such Person is an
Excepted Holder or a Permitted Holder (in which case the Excepted Holder Limit
shall be applicable); (ii) no Person may Beneficially Own or Constructively Own
Equity Shares of the Trust in excess of 9.8 percent of the value of the total
outstanding Equity Shares of the Trust, unless such Person is an Excepted Holder
or a Permitted Holder (in which case the Excepted Holder Limit shall be
applicable); (iii) no Person may Beneficially Own or Constructively Own Equity
Shares that would result in the Trust being "closely held" under Section 856(h)
of the Code or otherwise cause the Trust to fail to qualify as a REIT; and (iv)
no Person may Transfer Equity Shares if such Transfer would result in Equity
Shares of the Trust being owned by fewer than 100 Persons. Any Person who
Beneficially Owns or Constructively Owns or attempts to Beneficially Own or
Constructively Own Equity Shares which cause or will cause a Person to
Beneficially Own or Constructively Own Equity Shares in excess or in violation
of the above limitations must immediately notify the Trust. If any of the
restrictions on transfer or ownership are violated, the Equity Shares
represented hereby will be automatically transferred to a Trustee of a
Charitable Trust for the benefit of one or more Charitable Beneficiaries. In
addition, upon the occurrence of certain events, attempted Transfers in
violation of the restrictions described above may be void AB INITIO. All
capitalized terms in this legend have the meanings defined in the Declaration of
Trust of the Trust, as the same may be amended from time to time, a copy of
which, including the restrictions on transfer and ownership, will be furnished
to each holder of Equity Shares of the Trust on request and without charge. Such
request must be made to the Secretary of the Trust at its principal office or to
the Transfer Agent.

             KEEP THIS CERTIFICATE IN A SAFE PLACE. IF LOST, STOLEN
          OR DESTROYED, THE TRUST WILL REQUIRE A BOND OF INDEMNITY AS A
             CONDITION TO THE ISSUANCE OF A REPLACEMENT CERTIFICATE.

     The following abbreviations, when used in the inscription on the face of
this Certificate, shall be construed as if they were written out in full
according to applicable laws or regulations.

<TABLE>
<S>            <C>                        <C>             <C>                         <C>          <C>
TEN COM        -- as tenants in common    UNIF GIFT       ------- Custodian  ----     UNIF TRAN    ------- Custodian  ------
TEN ENT        -- as tenants by the       MIN ACT          (Cust)           (Minor)   MIN ACT      (Cust)             (Minor)
               entireties                                 Under Uniform Gifts to                   Under Uniform Transfers
JT TEN         -- as joint tenants with                   Minors Act of __________                 to Minors Act of _________
               right of survivorship                                      (Date)                                     (Date)
               and not as tenants in
               common


     FOR VALUE RECEIVED,                                         hereby sells, assigns and transfers unto
                         ---------------------------------------

  -------------------------------------------------------------------------------------------------------
                     (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE OF ASSIGNEE)



     _______________________(_________________) Series F Cumulative Redeemable Preferred Shares of beneficial interest of the Trust
represented by this Certificate and does not hereby irrevocably constitute and appoint ______________________________
___________ Attorney to transfer the said shares on the books of the Trust, with full power of substitution in the premises.


Dated:
         ------------------


                                                     --------------------------
                                                     NOTICE: THE SIGNATURE TO
                                                     THIS ASSIGNMENT MUST
                                                     CORRESPOND WITH THE NAME AS
                                                     WRITTEN UPON THE FACE OF
                                                     THIS CERTIFICATE IN EVERY
                                                     PARTICULAR, WITHOUT
                                                     ALTERATION OR ENLARGEMENT
                                                     OR ANY CHANGE WHATEVER.

</TABLE>