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                                                                     EXHIBIT 3.6


                            CERTIFICATE OF AMENDMENT

                                       OF

                          CERTIFICATE OF INCORPORATION

                                       OF

                               QLOGIC CORPORATION
                             A DELAWARE CORPORATION


        (Pursuant to Section 242 of the Delaware General Corporation Law)


QLOGIC CORPORATION, a corporation organized and existing under and by virtue of
the General Corporation Law of the State of Delaware,


DOES HEREBY CERTIFY:


FIRST: That at a meeting of the Board of Directors of QLogic Corporation,
resolutions were duly adopted setting forth proposed amendments of the
Certificate of Incorporation of said corporation, declaring said amendments to
be advisable and directing that said amendments be submitted to the stockholders
of said corporation for consideration thereof. The resolutions setting forth the
proposed amendments are as follows:



         RESOLVED, that, effective as of February 15, 1999, the second and third
         sentences of the first paragraph of ARTICLE IV: "Authorized Capital
         Stock," of the corporation's Certificate of Incorporation be amended
         and restated in their entirety as follows:

                           "The amount of total authorized capital stock of the
                  corporation is 51,000,000 shares, divided into 50,000,000
                  shares of Common Stock, par value $0.05 per share, and
                  1,000,000 shares of Preferred Stock, par value $0.10 per
                  share. Upon the effectiveness of this Certificate of Amendment
                  of Certificate of Incorporation, each issued and outstanding
                  share of the



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                  corporation's Common Stock, par value $0.10 per share, shall
                  automatically and without any action on the part of the holder
                  thereof be reclassified as and changed into two shares of the
                  corporation's Common Stock, par value $0.05 per share."


         RESOLVED FURTHER, that the foregoing amendment of the Certificate of
         Incorporation shall in no way modify, amend or supersede the
         corporation's Certificate of Designation filed in the office of the
         Secretary of State of Delaware on June 14, 1996, which is hereby
         affirmed.

SECOND: That thereafter, the holders of the necessary number of shares of
capital stock of the Corporation, as required by statute and by the Certificate
of Incorporation, gave their written consent in favor of the foregoing amendment
in accordance with the provisions of Section 228 of the Delaware General
Corporation Law, and written notice thereof was provided to stockholders who did
not so consent.

THIRD: That said amendments were duly adopted in accordance with the provisions
of Section 242 of the Delaware General Corporation Law.

IN WITNESS WHEREOF, QLogic Corporation has caused this Certificate of Amendment
to be signed by its duly authorized Chief Executive Officer, H.K. Desai, and
attested by its duly authorized Secretary, Michael R.
Manning, this 5 day of February, 1999.


                                               QLOGIC CORPORATION,
                                               a Delaware corporation



                                               By: /s/ H.K. Desai
                                                   -----------------------------
                                                   H.K. Desai,
                                                   Chief Executive Officer

ATTEST:


/s/ Michael R. Manning
--------------------------------
Michael R. Manning,
Secretary



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