COPT DEFENSE PROPERTIES — Director's Dealing 2011

May 13, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: CORPORATE OFFICE PROPERTIES TRUST (OFC)
CIK: 0000860546
Period of Report: 2011-05-12

Reporting Person: BRADY THOMAS F (Director)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-05-12	Common Shares	M	5000	$13.40	Acquired	9000	Direct
2011-05-12	Common Shares	S	5000	$34.257	Disposed	4000	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2011-05-12	Options of Common Stock	$13.40	M	5000	Acquired	2012-03-16	Common Shares (5000)	Direct

Footnotes

F1: These restricted shares were granted as part of annual trustee compensation and will vest in one year