As filed with the Securities and Exchange Commission on May 18, 2007

Registration No. 333-          

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

BROCADE COMMUNICATIONS SYSTEMS, INC.

(Exact name of Registrant as specified in its charter)

Delaware	77-0409517
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification Number)

1745 Technology Drive

San Jose, CA 95110

(408) 333-8000

(Address, including zip code, and telephone number, including area code, of Registrant’s principal executive offices)

Tyler Wall, Esq.

Vice President and General Counsel

Brocade Communications Systems, Inc.

1745 Technology Drive

San Jose, CA 95110

(408) 333-8000

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Katharine A. Martin, Esq.

Bradley L. Finkelstein, Esq.

Wilson Sonsini Goodrich & Rosati,

Professional Corporation

650 Page Mill Road

Palo Alto, California 94304

(650) 493-9300

Approximate date of commencement of proposed sale to the public:  From time to time after the effective date of this Registration Statement.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.  o

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.  þ

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  o

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  o

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box.  þ

If this Form is post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413 (b) under the Securities Act, check the following box.  o

CALCULATION OF REGISTRATION FEE

		Proposed Maximum	Proposed	Amount of
Title of Each Class of	Amount to be	Offering Price	Maximum	Registration
Securities to be Registered	Registered	per Unit	Offering Price(1)	Fee
Debt Securities
Common Stock, $0.001 par value per share
Preferred Stock, $0.001 par value per share
Depositary Shares	(1)	(1)	(1)
Warrants
Subscription Rights
Total

(1) An indeterminate amount of each identified class of securities to be offered at indeterminate prices is being registered pursuant to this registration statement. The registrant is deferring payment of the registration fee pursuant to Rule 456(b) and is omitting this information in reliance on Rule 456(b) and Rule 457(r). Any registration fees will be paid subsequently on a pay-as-you-go basis in accordance with Rule 457(r).

PROSPECTUS

Debt Securities
Common Stock
Preferred Stock
Depositary Shares
Warrants
Subscription Rights

We may offer from time to time debt securities, common stock, preferred stock, depositary shares, warrants, or subscription rights. The debt securities, preferred stock, warrants and subscription rights may be convertible into or exercisable or exchangeable for common or preferred stock or other securities of our company or debt or equity securities of one or more other entities. We will provide the specific terms of any offering and the offered securities in supplements to this prospectus. You should read this prospectus and any supplement carefully before you invest. Brocade Communications Systems, Inc.’s common stock is traded on the Nasdaq Global Select Market under the symbol “BRCD.” On May 17, 2007, the last reported sale price for our common stock was $9.32 per share.

We may offer and sell these securities to or through one or more underwriters, dealers and agents, or directly to purchasers, on an immediate, continuous or delayed basis. The names of any underwriters will be stated in the applicable prospectus supplement.

This prospectus may not be used to sell securities unless accompanied by a prospectus supplement which will describe the method and terms of the related offering.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

This prospectus is dated May 18, 2007

TABLE OF CONTENTS

	Page
Summary		1
Forward-Looking Statements		1
Use of Proceeds		2
Ratio of Earnings to Fixed Charges		2
Description of the Securities		2
Description of the Debt Securities		2
Legal Matters		4
Experts		4
Where You Can Find More Information		5
Incorporation of Certain Information by Reference		5
EXHIBIT 4.1
EXHIBIT 5.1
EXHIBIT 12.1
EXHIBIT 23.1
EXHIBIT 23.2
EXHIBIT 23.3
EXHIBIT 23.4
EXHIBIT 25.1

No person has been authorized to give any information or make any representations in connection with this offering other than those contained or incorporated by reference in this prospectus and any accompanying prospectus supplement in connection with the offering described in this prospectus and any accompanying prospectus supplement, and, if given or made, such information or representations must not be relied upon as having been authorized by us. Neither this prospectus nor any prospectus supplement shall constitute an offer to sell or a solicitation of an offer to buy offered securities in any jurisdiction in which it is unlawful for such person to make such an offering or solicitation. Neither the delivery of this prospectus or any prospectus supplement nor any sale made hereunder shall under any circumstances imply that the information contained or incorporated by reference in this prospectus or in any prospectus supplement is correct as of any date subsequent to the date of this prospectus or of any prospectus supplement.

SUMMARY

About This Prospectus

This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or the SEC, using a “shelf” registration process. Under this shelf process, we may sell any combination of the securities described in this prospectus in one or more offerings.

This prospectus provides you with a general description of the securities offered by us. Each time we sell securities, we will provide a prospectus supplement that will contain specific information about the terms of that offering. The prospectus supplement may also add to, update or change information contained in the prospectus and, accordingly, to the extent inconsistent, information in this prospectus is superseded by the information in the prospectus supplement.

The prospectus supplement to be attached to the front of this prospectus may describe, as applicable: the terms of the securities offered, the initial public offering price, the price paid for the securities, net proceeds and the other specific terms related to the offering of these securities.

You should only rely on the information contained or incorporated by reference in this prospectus and/or any prospectus supplement. We have not authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. We are not making offers to sell these securities in any jurisdiction where the offer or sale is not permitted. You should not assume that the information in this prospectus or any prospectus supplement is accurate as of any date other than the date on the cover of the applicable document and that any information we have incorporated by reference is accurate only as of the date of the document incorporated by reference. Our business, financial condition, results of operations and prospects may have changed since that date.

In this prospectus, unless we state otherwise, the “Company,” “we,” “us,” “our” and “Brocade” refer to Brocade Communications Systems, Inc. and its consolidated subsidiaries.

Brocade Communications Systems, Inc.

Brocade develops, markets, sells, and supports data storage networking products and services, offering a line of storage networking products that enable companies to implement and manage highly available, scalable, and secure environments for data storage networks. The Brocade family of storage area networking, or SAN, products is designed to help companies reduce the cost and complexity of managing business information within a data storage environment, ensure high availability of mission critical applications and serve as a platform for corporate data backup and disaster recovery. In addition, the Brocade family of application infrastructure solutions extends the ability to proactively manage and optimize application and information resources across the enterprise. Brocade products are installed around the world at companies, institutions, and other entities ranging from large enterprises to small and medium size businesses. Brocade products and services are marketed, sold, and supported worldwide to end-user customers through distribution partners, including original equipment manufacturers, or OEMs, distributors, systems integrators and value-added resellers, and by Brocade directly.

FORWARD-LOOKING STATEMENTS

This prospectus and the information incorporated by reference in this prospectus contain forward-looking statements made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. All statements other than statements of historical fact are statements that could be deemed forward-looking statements, including, but not limited to, projections of revenue, margins, expenses, tax provisions, earnings, cash flows, benefit obligations, share repurchases or other financial items; any statements of the plans, strategies and objectives of management for future operations; any statements concerning expected development, performance or market share relating to products or services; any statements regarding future economic conditions or performance; any statements regarding pending investigations, claims or disputes; any statements of expectation or belief; and any statements of assumptions underlying any of the foregoing. These statements are based on current expectations,

1

estimates, forecasts, and projections about the industries in which we operate and the beliefs and assumptions of our management. Readers are cautioned that these forward-looking statements are only predictions and are subject to risks, uncertainties, and assumptions that are difficult to predict, including those risk factors set forth in the documents incorporated by reference into this prospectus. Therefore, actual results may differ materially and adversely from those expressed in any forward-looking statements. Further, we undertake no obligation to revise or update any forward-looking statements for any reason.

USE OF PROCEEDS

Unless otherwise indicated in the prospectus supplement, we intend to use the net proceeds from the offerings for general corporate purposes and to fund possible acquisitions.

RATIO OF EARNINGS TO FIXED CHARGES

The ratio of earnings to fixed charges for each of the periods indicated is as follows.

	Quarter Ended			Fiscal Year Ended
	January 27,			October 28,			October 29,			October 30,		October 25,		October 26,
	2007			2006			2005			2004(2)		2003(2)		2002
Ratio of earnings to fixed charges(1)		5.7	x		10.2	x		5.9	x		—		—		7.2x

(1)

The ratio of earnings to fixed charges was computed by dividing earnings (loss) from continuing operations before taxes by fixed charges from continuing operations for the periods indicated. Fixed charges from continuing operations include (i) interest expense and amortization of debt discount and issuance costs on all indebtedness, and (ii) one-third of all rental expense, which the Company considers to be a reasonable approximation of the interest factor included in rental expense.

(2)

Earnings were inadequate to cover fixed charges. For the years ended October 30, 2004 and October 25, 2003, the Company needed additional earnings of $19.6 million and $134.7 million, respectively, to achieve a ratio of earnings to fixed charges of 1.0x.

DESCRIPTION OF THE SECURITIES

We may issue from time to time, in one or more offerings the following securities:

•  debt securities, which may be senior or subordinated, and which may be convertible into our common stock or be non-convertible;

•  shares of common stock;

•  shares of preferred stock;

•  depositary shares;

•  warrants exercisable for debt securities, common stock or preferred stock; and

•  subscription rights.

We will set forth in the applicable prospectus supplement a description of the debt securities, common stock, preferred stock, depositary shares, warrants and subscription rights that may be offered under this prospectus. The terms of the offering of securities, the initial offering price and the net proceeds to us will be contained in the prospectus supplement, and other offering material, relating to such offer.

DESCRIPTION OF THE DEBT SECURITIES

This section describes the general terms and provisions of any debt securities that we may offer in the future. A prospectus supplement relating to a particular series of debt securities will describe the material terms of that

2

particular series and to the extent to which the general terms and provisions contained herein apply to that particular series.

Debt securities may be issued in separate series without limitation as to aggregate principal amount. We may specify a maximum aggregate principal amount for the debt securities of any series. We are not limited as to the amount of debt securities we may issue under the indenture. Unless otherwise provided in a prospectus supplement, a series of debt securities may be reopened for issuance of additional debt securities of such series.

Events of Default

The indenture defines an event of default with respect to any series of debt securities as one or more of the following events:

•  failure to pay principal of or any premium on any debt security of that series when due;

•  failure to pay any interest on any debt security of that series for 30 days when due;

•  failure to make any sinking fund payment for 30 days when due;

•  failure to perform any other covenant in the indenture if that failure continues for 90 days after we are given the notice required in the indenture;

•  our or our significant subsidiary’s (as defined in Regulation S-X promulgated under the Securities Act of 1933, as amended,) bankruptcy, insolvency or reorganization; and

•  any other event of default specified in the prospectus supplement.

An event of default of one series of debt securities is not necessarily an event of default for any other series of debt securities.

If an event of default, other than an event of default described in clause (5) above solely with respect to us, shall occur and be continuing, either the trustee or the holders of at least 25% in aggregate principal amount of the outstanding securities of that series may declare the principal amount of the debt securities of that series to be due and payable immediately. If an event of default described in clause (5) above shall occur solely with respect to us, the principal amount of all the debt securities of that series will automatically become immediately due and payable.

After acceleration the holders of a majority in aggregate principal amount of the outstanding securities of that series, under certain circumstances, may rescind and annul such acceleration if all events of default, other than the non-payment of accelerated principal, or other specified amount, have been cured or waived.

If a default or event of default has occurred and the trustee has received notice of the default or event of default in accordance with the indenture, the trustee must mail to each holder a notice of the default or event of default within 30 days after receipt of the notice. However, the trustee need not mail the notice if the default or event of default (a) has been cured or waived; or (b) is not in the payment of any amounts due with respect to any security or the failure to convert any security in accordance with the indenture and the trustee in good faith determines that withholding the notice is in the best interests of holders. In addition, the trustee shall give the holders of securities of such series notice of such default or event of default actually known to it as and to the extent provided by the Trust Indenture Act.

Satisfaction and Discharge

We may be discharged from our obligations on the debt securities of any series if we deposit enough cash or U.S. government obligations with the trustee to pay all of the principal, interest and any premium due to the stated maturity date or redemption date of the debt securities and satisfy certain other conditions precedent. We may be so discharged only if (i) all of the securities of such series have been delivered to the trustee for cancellation (subject to certain exceptions) or (ii) all such Securities not theretofore delivered to the trustee for cancellation have become due and payable, or will become due and payable at their Stated Maturity within one year, or if redeemable at our option, are to be called for redemption within one year under arrangements satisfactory to the trustee for the giving of notice of redemption by the trustee in our name and at our expense.

3

Upon such satisfaction and discharge of the indenture with respect to any series of securities, the indenture shall cease to be of further effect with respect to such series of securities, except as to any surviving rights of registration of transfer or exchange of securities expressly provided for in the indenture or any other surviving rights expressly provided for in a supplemental indenture for a series of Securities.

Upon any satisfaction and discharge of the indenture with respect to a series of securities, and notwithstanding any other provision of the indenture to the contrary, any and all defaults and events of default of a type described in the fourth, fifth and sixth bullet points under the section “ — Events of Default” then existing shall be deemed cured with respect to such series, except to the extent such covenants or terms expressly survive such satisfaction and discharge as provided in the indenture or as provided with respect to securities of such series, and any acceleration or right of acceleration with respect thereto shall be deemed immediately rescinded and annulled and of no further force or effect, without any further action by us or the trustee.

Use of Proceeds

The use of proceeds for a series of debt securities will be specified in a prospectus supplement.

Compliance Certificates and Opinions

Upon any application or request by us to the trustee to take any action under any provision of the indenture, we will furnish to the trustee such certificates and opinions as may be required under the Trust Indenture Act.

LEGAL MATTERS

Wilson Sonsini Goodrich & Rosati, Professional Corporation, Palo Alto, California, will pass upon the validity of the issuance of the securities offered by any prospectus supplement for us.

EXPERTS

The consolidated financial statements of Brocade Communications Systems, Inc. and its subsidiaries as of October 28, 2006 and October 29, 2005 and for each of the years in the three-year period ended October 28, 2006, the related financial statement schedule and management’s assessment of the effectiveness of internal control over financial reporting as of October 28, 2006, are incorporated by reference herein in reliance on the reports of KPMG LLP, independent registered public accounting firm, also incorporated by reference herein, and upon the authority of said firm as experts in auditing and accounting.

The financial statements and the related financial statement schedule as of and for the years ended January 31, 2006 and 2005, incorporated by reference in this prospectus have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their report, which is incorporated by reference herein, and has been so incorporated in reliance upon the report of such firm given upon their authority as experts in accounting and auditing.

The financial statements of McDATA Corporation as of January 31, 2004 and for the year ended January 31, 2004, are incorporated by reference herein and have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

The consolidated financial statements and schedules of Computer Network Technology Corporation (“CNT”) (which was acquired by McData Corporation on June 1, 2005) as of January 31, 2005 and 2004, and for each of the years then ended, have been incorporated by reference herein in reliance upon the reports of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing. The audit report on management’s assessment of the effectiveness of internal control over financial reporting and the effectiveness of internal control over financial reporting as of January 31, 2005, expresses their opinion that CNT did not maintain effective internal control over financial reporting as of January 31, 2005 because of the effects of material weaknesses on the achievement of the objectives of the control

4

criteria and contains an explanatory paragraph that the following material weaknesses were identified as of January 31, 2005:

•  Procedures reconciling CNT’s offsite finished goods inventory to the general ledger were not adequate to ensure that the general ledger amounts represented actual offsite finished goods inventory. Specifically, CNT’s personnel were not adequately trained in CNT’s policies and procedures for physical tracking and recording changes to offsite finished goods inventory. This deficiency in internal control resulted in material misstatements of finished goods inventory and cost of products sold and operating expenses as of January 31, 2005.

•  CNT’s information technology access controls were not designed to prevent CNT personnel from accessing inventory accounting information and initiating erroneous accounting entries affecting amounts recorded as finished goods inventory. Specifically, this deficiency contributed to the aforementioned material misstatements in CNT’s interim and annual financial information.

WHERE YOU CAN FIND MORE INFORMATION

We file reports, proxy statements and other information with the Securities and Exchange Commission, in accordance with the Securities Exchange Act of 1934, as amended. You may read and copy our reports, proxy statements and other information filed by us at the Public Reference Room of the Securities and Exchange Commission at 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information about the public reference rooms. Our reports, proxy statements and other information filed with the SEC are available to the public over the Internet at the SEC’s website at http://www.sec.gov and at our website at http://www.brocade.com. However, information on the Commission’s website and our website does not constitute a part of this prospectus.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The Commission allows us to “incorporate by reference” into this prospectus the information we filed with the Commission. This means that we can disclose important information by referring you to those documents. The information incorporated by reference is considered to be a part of this prospectus. Information that we file later with the Commission will automatically update and supersede this information. We incorporate by reference the documents listed below (other than any portions of such documents that are not deemed “filed” under the Exchange Act in accordance with the Exchange Act and applicable SEC rules) and any future filings made by us with the Commission (other than any portions of such documents that are not deemed “filed” under the Exchange Act in accordance with the Exchange Act and applicable SEC rules) under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act until our offering is complete:

•  Our Annual Report on Form 10-K for the fiscal year ended October 28, 2006;

•  Our Quarterly Report on Form 10-Q for the fiscal quarter ended January 27, 2007;

•  Our Current Reports on Form 8-K filed on November 24, 2006, November 30, 2006, January 24, 2007, February 2, 2007, February 16, 2007, April 16, 2007, April 25, 2007; May 17, 2007 and May 18, 2007 and

•  The description of our common stock contained in the registration statement on Form 8-A, filed with the Commission on or about March 19, 1999, and any amendment or report filed for the purpose of updating such description.

You may request a copy of these filings, at no cost, by writing or telephoning us at the following address:

Investor Relations Department

Brocade Communications Systems, Inc.

1745 Technology Drive

San Jose, CA 95110

(408) 333-8000

5

Part II

Information Not Required in the Prospectus

Item 14.   Other Expenses of Issuance and Distribution

The following table sets forth the best estimate of the Registrant as to its anticipated expenses and costs (other than underwriting discounts and commissions) expected to be incurred in connection with a distribution of securities registered hereby:

Securities and Exchange Commission registration fee	(1	)
Trustee’s and transfer agent’s fees and expenses	(2	)
Accounting fees and expenses	(2	)
Legal fees and expenses	(2	)
Printing and engraving	(2	)
Miscellaneous	(2	)
Total	(2	)(3)

(1)	To be deferred pursuant to Rule 456(b) calculated in connection with the offering of securities under this registration statement pursuant to Rule 457(r).
(2)	The amount of securities and number of offerings are indeterminable and the expenses cannot be estimated at this time.
(3)	Will exclude SEC registration fee which is being deferred pursuant to Rule 456(b) calculated in connection with the offering of securities under this registration statement pursuant to Rule 457(r).

Item 15.   Indemnification of Directors and Officers

Section 145(a) of the Delaware General Corporation Law (the “DGCL”) provides in relevant part that “[a] corporation shall have power to indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative (other than an action by or in the right of the corporation) by reason of the fact that the person is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise, against expenses (including attorneys’ fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by the person in connection with such action, suit or proceeding if the person acted in good faith and in a manner the person reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding, had no reasonable cause to believe the person’s conduct was unlawful.” With respect to derivative actions, Section 145(b) of the DGCL provides in relevant part that “[a] corporation shall have power to indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action or suit by or in the right of the corporation to procure a judgment in its favor...[by reason of the person’s service in one of the capacities specified in the preceding sentence] against expenses (including attorneys’ fees) actually and reasonably incurred by the person in connection with the defense or settlement of such action or suit if the person acted in good faith and in a manner the person reasonably believed to be in or not opposed to the best interests of the corporation and except that no indemnification shall be made in respect of any claim, issue or matter as to which such person shall have been adjudged to be liable to the corporation unless and only to the extent that the Court of Chancery or the court in which such action or suit was brought shall determine upon application that, despite the adjudication of liability but in view of all the circumstances of the case, such person is fairly and reasonably entitled to indemnity for such expenses which the Court of Chancery or such other court shall deem proper.”

The Registrant’s Amended and Restated Certificate of Incorporation provides that to the fullest extent permitted by the DGCL, no director of the Registrant shall be personally liable to the Registrant or its stockholders for monetary damages for breach of fiduciary duty as a director. The Amended and Restated Certificate of Incorporation also provides that no amendment or repeal of such provision shall apply to or have any effect on the

II-1

right to indemnification permitted thereunder with respect to claims arising from acts or omissions occurring in whole or in part before the effective date of such amendment or repeal whether asserted before or after such amendment or repeal.

The Registrant’s bylaws provide for the indemnification of officers, directors and third parties acting on behalf of the Registrant if such person acted in good faith and in a manner reasonably believed to be in and not opposed to the best interest of the Registrant, and, with respect to any criminal action or proceeding, the indemnified party had no reason to believe his or her conduct was unlawful. The Registrant has entered into indemnification agreements with its directors and executive officers and intends to enter into indemnification agreements with any new directors and executive officers in the future.

The Registrant carries officer and director liability insurance with respect to certain matters, including matters arising under the Securities Act.

II-2

Item 16.   Exhibits

EXHIBIT INDEX

The following exhibits are filed herewith or incorporated by reference herein:

Exhibit				Incorporated by Reference			Filed
Number			Exhibit Title	Form	File No.	Filing Date	Herewith
	1	.1	Form of Underwriting Agreement*
	3	.1	Amended and Restated Certificate of Incorporation of the Registrant	10-K		January 24, 2002
	3	.2	Certificate of Designation of Rights, Preferences and Privileges of Series A Participating Preferred Stock of Brocade Communications Systems, Inc.	8-A		February 11, 2002
	3	.3	Certificate of Elimination of Series A Participating Preferred Stock of Brocade Communications Systems, Inc.	8-K		February 16, 2007
	3	.4	Amended and Restated Bylaws of the Registrant, as currently in effect	8-K		April 25, 2007
	3	.5	Specimen Certificate of Common Stock	S-1	333-74711	April 28, 1999
	4	.1	Form of Indenture				X
	4	.2	Form of Debt Security (included in Exhibit 4.1)				X
	4	.3	Form of Certificate of Designation*
	4	.4	Form of Preferred Stock Certificate*
	4	.5	Form of Deposit Agreement*
	4	.6	Form of Depositary Receipt*
	4	.7	Form of Warrant Agreement*
	4	.8	Form of Warrant Certificate*
	5	.1	Opinion of Wilson Sonsini Goodrich & Rosati, Professional Corporation				X
	12	.1	Computation of Ratio of Earnings to Fixed Charges				X
	23	.1	Consent of KPMG LLP				X
	23	.2	Consent of Deloitte & Touche LLP				X
	23	.3	Consent of PricewaterhouseCoopers LLP				X
	23	.4	Consent of KPMG LLP				X
	23	.5	Consent of Wilson Sonsini Goodrich & Rosati, Professional Corporation (included in Exhibit 5.1)
	24	.1	Power of Attorney of certain directors and officers of Brocade Communications Systems, Inc. (see page II-6 of this Form S-3)
	25	.1	Form T-1 Statement of Eligibility of Trustee for Indenture under the Trust Indenture Act of 1939				X

* To be filed by amendment or as an exhibit to a report pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended and incorporated herein by reference.

II-3

Item 17.   Undertakings

(a) The undersigned Registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) to include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

(ii) to reflect in the prospectus any facts or events arising after the effective date of this registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in this registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement;

(iii) to include any material information with respect to the plan of distribution not previously disclosed in this registration statement or any material change to such information in this registration statement;

provided, however, that paragraphs (a)(1)(i), (a)(1)(ii) and (a)(1)(iii) of this section do not apply if the registration statement is on Form S-3 and the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the Registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in this registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

(2) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered herein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(5) That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser:

(A) Each prospectus filed by the Registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

(B) Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5), or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii) or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act of 1933 shall be deemed to be part of and included in this registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made in a registration statement or a prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of this registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was

II-4

made in this registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date.

(6) That, for the purpose of determining liability of the Registrant under the Securities Act of 1933 to any purchaser in the initial distribution of the securities:

The undersigned Registrant undertakes that in a primary offering of securities of the undersigned Registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned Registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i) Any preliminary prospectus or prospectus of the undersigned Registrant relating to the offering required to be filed pursuant to Rule 424;

(ii) Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned Registrant or used or referred to by the undersigned Registrant;

(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned Registrant or its securities provided by or on behalf of the undersigned Registrant; and

(iv) Any other communication that is an offer in the offering made by the undersigned Registrant to the purchaser.

(b) The undersigned Registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the Registrant’s annual report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in this registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(h) Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the Registrant pursuant to the foregoing provisions, or otherwise, the Registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act of 1933 and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the Registrant of expenses incurred or paid by a director, officer or controlling person of the Registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the Registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act of 1933 and will be governed by the final adjudication of such issue.

(i) The undersigned registrant hereby undertakes that:

(1) For purposes of determining any liability under the Securities Act of 1933, the information omitted from the form of prospectus filed as part of this registration statement in reliance upon Rule 430A and contained in a form of prospectus filed by the registrant pursuant to Rule 424(b)(1) or (4) or 497(h) under the Securities Act of 1933 shall be deemed to be part of this registration statement as of the time it was declared effective.

(2) For the purpose of determining any liability under the Securities Act of 1933, each post-effective amendment that contains a form of prospectus shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(j) The undersigned Registrant hereby undertakes to file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of Section 310 of the Trust Indenture Act in accordance with the rules and regulations prescribed by the Commission under Section 305(b)(2) of the Trust Indenture Act.

II-5

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the registrant certifies that it has reasonable grounds to believe it meets all of the requirements for filing on Form S-3 and has duly caused this Registration Statement on Form S-3 to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of San Jose, State of California on May 11, 2007.

BROCADE COMMUNICATIONS SYSTEMS, INC.

By:  /s/  Michael Klayko

Michael Klayko

Chief Executive Officer

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Michael Klayko and Richard Deranleau, and each of them acting individually, as his true and lawful attorneys-in-fact and agents, each with the full power of substitution and resubstitution, for him and his name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement, and to sign any registration statement for the same offering covered by this Registration Statement that are to be effective upon filing pursuant to Rule 462(b) promulgated under the Securities Act, and all post-effective amendments thereto, and to file the same, with all exhibits thereto and all documents in connection therewith, with the SEC, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that such attorneys-in-fact and agents or any of them, or his or their substitute or substitutes, may lawfully do or cause to be done by virtue hereof. This power of attorney may be executed in counterparts.

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

Signature	Title	Date
/s/  Michael Klayko Michael Klayko	Chief Executive Officer (Principal Executive Officer)	May 11, 2007
/s/  Richard Deranleau Richard Deranleau	Vice President of Finance and Chief Financial Officer (Principal Financial and Accounting Officer)	May 11, 2007
/s/  Dave House Dave House	Chairman of the Board of Directors	May 11, 2007
/s/  Renato DiPentima Renato DiPentima	Director	May 11, 2007
/s/  John W. Gerdelman John W. Gerdelman	Director	May 11, 2007
/s/  Glenn Jones Glenn Jones	Director	May 11, 2007

II-6

Signature	Title	Date
/s/  L. William Krause L. William Krause	Director	May 11, 2007
/s/  Mike Rose Mike Rose	Director	May 11, 2007
/s/  Sanjay Vaswani Sanjay Vaswani	Director	May 11, 2007
/s/  Robert R. Walker Robert R. Walker	Director	May 11, 2007

II-7

EXHIBIT INDEX

				Incorporated
Exhibit				by Reference			Filed
Number			Exhibit Title	Form	File No.	Filing Date	Herewith
	1	.1	Form of Underwriting Agreement*
	3	.1	Amended and Restated Certificate of Incorporation of the Registrant	10-K		January 24, 2002
	3	.2	Certificate of Designation of Rights, Preferences and Privileges of Series A Participating Preferred Stock of Brocade Communications Systems, Inc.	8-A		February 11, 2002
	3	.3	Certificate of Elimination of Series A Participating Preferred Stock of Brocade Communications Systems, Inc.	8-K		February 16, 2007
	3	.4	Amended and Restated Bylaws of the Registrant, as currently in effect	8-K		April 25, 2007
	3	.5	Specimen Certificate of Common Stock	S-1	333-74711	April 28, 1999
	4	.1	Form of Indenture				X
	4	.2	Form of Debt Security (included in Exhibit 4.1)				X
	4	.3	Form of Certificate of Designation*
	4	.4	Form of Preferred Stock Certificate*
	4	.5	Form of Deposit Agreement*
	4	.6	Form of Depositary Receipt*
	4	.7	Form of Warrant Agreement*
	4	.8	Form of Warrant Certificate*
	5	.1	Opinion of Wilson Sonsini Goodrich & Rosati, Professional Corporation				X
	12	.1	Computation of Ratio of Earnings to Fixed Charges				X
	23	.1	Consent of KPMG LLP				X
	23	.2	Consent of Deloitte & Touche LLP				X
	23	.3	Consent of PricewaterhouseCoopers LLP				X
	23	.4	Consent of KPMG LLP				X
	23	.5	Consent of Wilson Sonsini Goodrich & Rosati, Professional Corporation (included in Exhibit 5.1)
	24	.1	Power of Attorney of certain directors and officers of Brocade Communications Systems, Inc. (see page II-6 of this Form S-3)
	25	.1	Form T-1 Statement of Eligibility of Trustee for Indenture under the Trust Indenture Act of 1939				X

* To be filed by amendment or as an exhibit to a report pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended and incorporated herein by reference.