EXHIBIT 5

OPINION AND CONSENT OF MORGAN, LEWIS & BOCKIUS LLP

May 15, 2003

Cisco Systems, Inc.

170 West Tasman Drive

San Jose, California 95134-1706

Re:    Cisco Systems, Inc. – Registration Statement for Offering of

          2,234,721 Shares of Common Stock                                     

Dear Ladies and Gentlemen:

We have acted as counsel to Cisco Systems, Inc., a California corporation (the “Company”), in connection with the registration on Form S-8 (the “Registration Statement”) under the Securities Act of 1933, as amended, of 2,234,721 shares of the Company’s common stock for issuance under the Okena, Inc. 1999 Stock Option and Grant Plan, Amended and Restated as of August 29, 2001 (the “Plan”).

This opinion is being furnished in accordance with the requirements of Item 8 of Form S-8 and Item 601(b)(5)(i) of Regulation S-K.

We have reviewed the Company’s charter documents and the corporate proceedings taken by the Company in connection with the assumption of the Plan and the outstanding options thereunder. Based on such review, we are of the opinion that if, as and when the shares of the Company’s common stock are issued and sold (and the consideration therefor received) pursuant to the provisions of option agreements duly authorized under the Plan and in accordance with the Registration Statement, such shares will be duly authorized, legally issued, fully paid and nonassessable.

We consent to the filing of this opinion letter as Exhibit 5 to the Registration Statement.

This opinion letter is rendered as of the date first written above and we disclaim any obligation to advise you of facts, circumstances, events or developments which hereafter may be brought to our attention and which may alter, affect or modify the opinion expressed herein. Our opinion is expressly limited to the matters set forth above and we render no opinion, whether by implication or otherwise, as to any other matters relating to the Company, the Plan or the shares of the Company’s common stock issuable under such plan.

Very truly yours,

/s/ Morgan, Lewis & Bockius LLP

MORGAN, LEWIS & BOCKIUS LLP