UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of

the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): December 9, 2009 (December 3, 2009)

BROCADE COMMUNICATIONS SYSTEMS, INC.

(Exact name of Registrant as specified in its charter)

1745 Technology Drive

San Jose, CA 95110

(Address, including zip code, of principal executive offices)

(408) 333-8000

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Changes to the Company’s Executive Leadership Plan (formerly Senior Leadership Plan)

On December 3, 2009, the Compensation Committee (the “Committee”) of the Board of Directors of Brocade Communications Systems, Inc. (the “Company”) amended the Company’s Senior Leadership Plan, now referred to as the Executive Leadership Plan (the “Leadership Plan”), effective as of fiscal year 2010. The criteria relating to the Company’s performance for the annual incentive targets under the Leadership Plan was amended to be subject to achievement of certain Company non-GAAP operating income targets (75%) and revenue targets (25%), as compared to certain Company non-GAAP operating income targets (100%) under the prior plan.

A copy of the Leadership Plan, as amended, is attached hereto as Exhibit 10.1 and is incorporated herein by reference.

New Form of Performance-Based Restricted Stock Unit Agreement

In addition, the Committee approved a new form of restricted stock unit agreement (market stock units) for the grant of certain performance-based equity awards under the Company’s 2009 Stock Plan. The terms of the form of restricted stock unit agreement provide for the grant of a variable number of restricted stock units subject to performance of the Company’s common stock as compared to the NASDAQ-100 Tracking Stock Index (NASDAQ: QQQQ) over a specified performance period. In addition, the restricted stock units may be subject to certain acceleration of vesting in connection with a change in control. For example, fifty percent (50%) of the restricted stock units may vest immediately upon the change in control, with the remaining fifty percent (50%) vesting upon the one-year anniversary of the change in control, unless vested earlier, in each case, in accordance with any applicable change of control agreement between grantee and the Company, and subject to continued employment through the applicable vesting date(s).

A copy of the form of the restricted stock unit agreement (market stock units) is attached hereto as Exhibit 10.2 and is incorporated herein by reference.

(d) Exhibits.

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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EXHIBIT INDEX

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