Exhibit 3.1

                              RESTATED AND AMENDED
                         CERTIFICATE OF INCORPORATION OF
                                 MICROMUSE INC.
                             a Delaware corporation

                     (Pursuant to Sections 228, 242 and 245
                    of the Delaware General Corporation Law)

      Micromuse Inc., a corporation organized and existing under the General
Corporation Law of the State of Delaware (the "General Corporation Law")

      DOES HEREBY CERTIFY:

      FIRST: That this corporation was originally incorporated on May 1, 1996,
pursuant to the General Corporation Law.

      SECOND: That the Board of Directors duly adopted resolutions proposing to
amend and restate the Amended and Restated Certificate of Incorporation of this
corporation, declaring said amendment and restatement to be advisable and in the
best interests of this corporation and its stockholders, and authorizing the
appropriate officers of this corporation to solicit the consent of the
stockholders therefor, which resolution setting forth the proposed amendment and
restatement is as follows:

      "RESOLVED, that the Restated Certificate of Incorporation of this
corporation, as amended, be amended and restated in its entirety as follows:

      The name of the corporation is Micromuse Inc. (the "Corporation").

      The address of the registered office of this corporation in the State of
Delaware is 1013 Centre Road, in the City of Wilmington, County of New Castle.
The name of its registered agent at such address is Corporation Services
Company.

      The nature of the business or purposes to be conducted or promoted is to
engage in any lawful act or activity for which corporations may be organized
under the General Corporation Law of Delaware.

      The Corporation is authorized to issue two classes of stock to be
designated common stock ("Common Stock") and preferred stock ("Preferred
Stock"). The number of shares of Common Stock authorized to be issued is Two
Hundred Million (200,000,000), par value $.01 per share, and the number of
Preferred Stock authorized to be issued is Five Million (5,000,000), par value
$.01 per share.

      The Preferred Stock may be issued from time to time in one or more series,
without further stockholder approval. The Board of Directors is hereby
authorized, in the resolution or resolutions adopted by the Board of

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                                 MICROMUSE INC.

Directors providing for the issue of any wholly unissued series of Preferred
Stock, within the limitations and restrictions stated in this Restated
Certificate of Incorporation (the "Restated Certificate"), to fix or alter the
dividend rights, dividend rate, conversion rights, voting rights, rights and
terms of redemption (including sinking fund provisions), the redemption price or
prices, and the liquidation preferences of any wholly unissued series of
Preferred Stock, and the number of shares constituting any such series and the
designation thereof, or any of them, and to increase or decrease the number of
shares of any series subsequent to the issue of shares of that series, but not
below the number of shares of such series then outstanding. In case the number
of shares of any series shall be so decreased, the shares constituting such
decrease shall resume the status that they had prior to the adoption of the
resolution originally fixing the number of shares of such series.

      Except as otherwise provided in this Restated Certificate, in furtherance
and not in limitation of the powers conferred by statute, the Board of Directors
is expressly authorized to make, repeal, alter, amend and rescind any or all of
the Bylaws of the Corporation.

      The number of directors of the Corporation shall be fixed from time to
time by a bylaw or amendment thereof duly adopted by the Board of Directors or
by the stockholders.

      The Board of Directors shall be and is divided into two classes, Class I
and Class II. Such classes shall be as nearly equal in number of directors as
possible. Each director shall serve for a term ending on the second annual
meeting following the annual meeting at which such director was elected;
provided, however, that the directors first elected to Class I shall serve for a
term ending on the annual meeting next following the end of fiscal year 1998 and
the directors first elected to Class II shall serve for a term ending on the
second annual meeting next following the end of fiscal year 1999. The foregoing
notwithstanding, each director shall serve until such director's successor shall
have been duly elected and qualified, unless such director shall resign, become
disqualified, disabled or shall otherwise be removed.

      At each annual election, directors chosen to succeed those whose terms
then expire shall be of the same class as the directors they succeed, unless by
reason of any intervening changes in the authorized number of directors, the
Board shall designate one or more directorships whose term then expires as
directorships of another class in order more nearly to achieve equality of
number of directors between the classes.

      Notwithstanding the rule that the two classes shall be as nearly equal in
number of directors as possible, in the event of any change in the authorized
number of directors each director then continuing to serve as such shall
nevertheless continue as a director of the class of which the director is a
member until the expiration of the director's current term, or the director's
prior death, resignation or removal. If any newly created directorship may,
consistently with the rule that the two classes shall be as nearly equal in
number of directors as possible, be allocated to either class, the Board shall
allocate it to that of the available class whose term of office is due to expire
at the earliest date following such allocation.

      Elections of directors need not be by written ballot unless the Bylaws of
the Corporation shall so provide.

      Except as otherwise provided in this Restated Certificate, any action
required or permitted to be taken by the stockholders of the Corporation must be
effected at an annual or special meeting of the stockholders of the Corporation,
and may not be effected by any consent in writing of such stockholders.

      A director of the Corporation shall not be personally liable to the
Corporation or its stockholders for monetary damages for breach of fiduciary
duty as a director, except for liability (i) for any breach of the director's
duty of loyalty to the Corporation or its stockholders, (ii) for acts or
omissions not in good faith or which involve

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                                 MICROMUSE INC.

intentional misconduct or a knowing violation of law, (iii) under Section 174 of
the Delaware General Corporation Law, or (iv) for any transaction from which the
director derived any improper personal benefit. If the Delaware General
Corporation Law is amended after approval by the stockholders of this Article to
authorize corporate action further eliminating or limiting the personal
liability of directors then the liability of a director of the Corporation shall
be eliminated or limited to the fullest extent permitted by the Delaware General
Corporation Law as so amended.

      Any repeal or modification of the foregoing provisions of this Article IX
by the stockholders of the Corporation shall not adversely affect any right or
protection of a director of the Corporation existing at the time of, or increase
the liability of any director of this Corporation with respect to any acts or
omissions of such director occurring prior to, such repeal or modification.

      The Corporation reserves the right to amend, alter, change or repeal any
provision contained in this Restated Certificate, in the manner now or hereafter
prescribed by statute, and all rights conferred upon stockholders herein are
granted subject to this reservation.

                                     * * * *

      THIRD: The foregoing Restated Certificate of Incorporation has been duly
adopted by the Corporation's Board of Directors in accordance with the
applicable provisions of Section 245 of the General Corporation Law of the State
of Delaware.

      IN WITNESS WHEREOF, the undersigned has signed this Certificate this 5th
day of December 2000.


                                        /s/ James B. De Golia
                                        ---------------------------------
                                        James B. De Golia
                                        Secretary