POWER OF ATTORNEY





 Know all by these presents, that the undersigned hereby constitutes and

appoints each of Anthony J. Massetti and Michael L. Hawkins, or either of them

signing singly, and with full power of substitution, the undersigned's true

and lawful attorney-in-fact to:



(1) prepare, execute in the undersigned's name and on the undersigned's

behalf, and submit to the United States Securities and Exchange Commission

(the 'SEC') a Form ID, including amendments thereto, and any other documents

necessary or appropriate to obtain codes and passwords enabling the

undersigned to make electronic filings with the SEC of reports required by

Section 16(a) of the Securities Exchange Act of 1934 or any rule or regulation

of the SEC;



(2) execute for and on behalf of the undersigned, in the undersigned's

capacity as an officer and/or director of QLogic Corporation, a Delaware

corporation (the 'Company'), Forms 3, 4 and 5 in accordance with Section 16(a)

of the Securities Exchange Act of 1934 and the rules thereunder;



(3) do and perform any and all acts for and on behalf of the undersigned

which may be necessary or desirable to complete and execute any such Form 3,

4 or 5, complete and execute any amendment or amendments thereto, and timely

file such form with the SEC and any stock exchange or similar authority; and



(4) take any other action of any type whatsoever in connection with the

foregoing which, in the opinion of such attorney-in-fact, may be of benefit

to, in the best interest of, or legally required by, the undersigned, it being

understood that the documents executed by such attorney-in-fact on behalf of

the undersigned pursuant to this Power of Attorney shall be in such form and

shall contain such terms and conditions as such attorney-in-fact may approve

in such attorney-in-fact's discretion.



       The undersigned hereby grants to each such attorney-in-fact full power

and authority to do and perform any and every act and thing whatsoever

requisite, necessary, or proper to be done in the exercise of any of the

rights and powers herein granted, as fully to all intents and purposes as the

undersigned might or could do if personally present, with full power of

substitution or revocation, hereby ratifying and confirming all that such

attorney-in-fact, or such attorney-in-fact's substitute or substitutes, shall

lawfully do or cause to be done by virtue of this power of attorney and the

rights and powers herein granted.  The undersigned acknowledges that the

foregoing attorneys-in-fact, in serving in such capacity at the request of

the undersigned, are not assuming, nor is the Company assuming, any of the

undersigned's responsibilities to comply with Section 16 of the Securities

Exchange Act of 1934.



 This Power of Attorney shall remain in full force and effect until

the undersigned is no longer required to file Forms 3, 4 and 5 with respect

to the undersigned's holdings of and transactions in securities issued by the

Company, unless earlier revoked by the undersigned in a signed writing

delivered to the foregoing attorneys-in-fact.  This Power of Attorney shall

supersede and replace any Power of Attorney previously granted by the

undersigned that relates to Section 16 filings of the undersigned relating

to the Company.





 IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney

to be executed as of this 17th day of February, 2005.







       /s/ Joel S. Birnbaum

       Joel S. Birnbaum