Limited Partnership Agreement

Exhibit 10.1.16

Fifteenth Amendment

To

Second Amended and Restated

Limited Partnership Agreement

Of

Corporate Office Properties, L.P.

This Fifteenth Amendment (the Amendment) to the Second 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 January 31, 2004, by the undersigned.

Recitals

A. The Partnership is a limited partnership organized under the Delaware Revised Uniform Limited Partnership Act and governed by that certain Second Amended and Restated Limited Partnership Agreement dated as of December 7, 1999 (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. Pursuant to Section 11.1 (b) (iii), the General Partner desires to amend the Partnership Agreement to reflect the admission, substitution, termination and/or withdrawal of various limited partners in accordance with the terms of the Partnership Agreement.

NOW THEREFORE, the General Partner, intending to be legally bound, hereby amends the Partnership Agreement as follows, effective as of the date first set forth above.

1. Exhibit 1, Schedule of Partners, as attached hereto and by this reference made a part hereof, is hereby substituted for and intended to replace any prior Exhibit 1 attached to a prior Amendment to the Partnership Agreement, and as attached hereto shall be a full and complete listing of all the general and limited partners of the Partnership as of the date of this Amendment, same being intended and hereby superceding all prior Exhibit 1 listings.

In Witness Whereof, the General Partner has executed this Amendment as of the day and year first above written.

	Corporate Office Properties Trust, a
	Maryland Real Estate Investment Trust
	By:	/s/ Xxxxx X. Xxxxxxx, Xx.
			Xxxxx X. Xxxxxxx, Xx.
			Executive Vice President

SCHEDULE OF PARTNERS

General Partner		Partnership Units
Corporate Office Properties Trust		27,291,612
Limited Partners and Preferred Limited Partners
Xxx X. Xxxxxxx		452,878
Xxxxxxx Equities, L.P.		2,995,439
Xxxx X. Xxxxxx, III		566,492
LBCW Limited Partnership		3,161,427
Xxxxxx X. Xxxxxx		434,910
Xxxxx X. Xxxxx		51,589
Xxxx X. De X. Xxxxxxx, Trustee of the Xxxx X. de X. Xxxxxxx Living Trust dated 9/12/88		300,625
Xxxxxxxxx X. Xxx Trust		29,140
June X. X. Xxx Trust		29,135
RP Investments, LLC		268,671
Xxxxxx X. Xxxxxxxxx		34,333
Xxxxxx Xxxx		22,889
Laswrence X. Xxxx		13,733
Xxxxxxxx X. Xxxxxxx		5,874
M.O.R. XXIX Associates Limited Partnership		148,381
M.O.R. 44 Gateway Associates Limited Partnership		1
Xxxx Xxxxxxxx		90,000
M.O.R. Commons Limited Partnership		7
Xxxx Xxxxxx Xx Xxxxx Xxxxxxx and Xxxxxx Xxxxxxx Xxxxxxx		50,476
Xxxxxxx Xxxxxxxxxx		90,905
Xxxx Xxxxxx		121,411
National Prostrate Cancer Coalition		500
Wildlands Conservancy		250
National Aquarium in Baltimore		300
University of Pennsylvania - Frineds of Penn Tennis		150
Xxxx Xxxxxxx University		300
Xxxxxxx School		500
		36,161,928

Exhibit 1 Addendum

Series Preferred Units		Preferred Limited Partner		No. of Preferred Units		Liquidation Preference Per Preferred Unit			Priority Percentage Return *		Priority		Conversion Factor		Conversion Commencement Date
B		General Partner		1,250,000		$	25		2.50	%	Senior		None		N/A
D		General Partner		544,000		$	25		1.00	%	Senior			**		**
E		General Partner		1,150,000		$	25		2.5625	%	Senior		None		N/A
F		General Partner		1,425,000		$	25		10.25	%	Senior		None		N/A
G		General Partner		2,200,000		$	25		8	%	Senior		None		N/A
H		General Partner		2,000,000		$	25		7.5	%	Senior		None		N/A

* Priority Return Percentage is expressed as a percentage of the Liquidation Preference per Distribution Period.  See the Agreement for the definitions of “Priority Return Percentage,” “Liquidation Preference” and “Distribution Period.”

** With respect to any series of Preferred Units issued to the General Partner pursuant to Section 4.2(B) of the Agreement, the Conversion Commencement Date and the applicable Conversion Factor shall correspond to the conversion commencement date and conversion factor of the related issuance of securities by the General Partner as provided in Section 4.2(B) of the Agreement.  See Section 9.8(A)(1) of the Agreement.