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                                                                     EXHIBIT 3.2


                        CERTIFICATE OF AMENDMENT TO THE
                          CERTIFICATE OF INCORPORATION
                                       OF
                            ILLUMINET HOLDINGS, INC.

        THE UNDERSIGNED DOES HEREBY CERTIFY that the following resolution was
duly adopted by the Board of Directors and approved by the stockholders of
Illuminet Holdings, Inc. (the "Corporation"), pursuant to Section 242 of the
General Corporation Law of the State of Delaware:

        RESOLVED, that the Certificate of Incorporation of the Corporation be
amended by deleting the first six paragraphs of Article FOURTH as they now exist
and inserting in lieu thereof the following:

                "FOURTH: The total number of shares of stock which the
        Corporation shall have authority to issue is One Hundred Fifty Seven
        Million Three Hundred Thousand (157,300,000) shares of stock, of which
        One Hundred Thousand (100,000) shares shall be Preferred Stock, par
        value $.01 per share ("Preferred Stock"), One Hundred Fifty Million
        (150,000,000) shares shall be Common Stock, par value $.01 per share
        ("Common Stock"), and Seven Million Two Hundred Thousand (7,200,000)
        shares shall be Class A Common Stock, par value $.01 per share ("Class A
        Common Stock").

                Each share of the Corporation's common stock outstanding on the
        date of effectiveness of this Article FOURTH shall automatically be
        reclassified into one share of Class A Common Stock, without any further
        action by the Corporation or any holder of stock of the Corporation.

                No holder of stock of the Corporation shall be entitled as such
        to any preemptive right to subscribe for, purchase or receive (i) any
        shares of stock of the Corporation at any time held in its treasury, or
        (ii) unissued shares of stock of the Corporation, whether authorized at
        present or hereafter authorized, or (iii) any issue of notes, bonds or
        debentures, whether or not convertible into any class of stock of the
        Corporation, or (iv) any issue of warrants, options or rights to
        subscribe for shares of any class of stock of the Corporation

                The powers, designations, preferences, qualifications,
        limitations, and relative rights of the shares of each class or series
        of stock are as follows:

        SUBDIVISION A. PREFERRED STOCK.

                The Preferred Stock shall be issued from time to time in one or
        more series with such distinctive serial designations and such voting


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        powers, full or limited, or no voting powers, and such designations,
        preferences and relative, participating, optional or other special
        rights, and qualifications, limitations or restrictions thereof, as
        shall be stated and expressed in the resolution or resolutions providing
        for the issue of such Preferred Stock adopted by the Board of Directors
        of the Corporation pursuant to the Board's authority to do so, which is
        hereby expressly vested in the Board.

        SUBDIVISION B. COMMON STOCK.

                1. DIVIDENDS AND LIQUIDATION. Subject to those rights expressly
        granted to the holders of Preferred Stock and the holders of Class A
        Common Stock, the holders of Common Stock shall have (a) the right to
        receive dividends, when and as declared by the Board of Directors of the
        Corporation out of the assets of the Corporation available for the
        payment of dividends under the laws of the State of Delaware, and (b)
        upon any liquidation (complete or partial), dissolution or winding up of
        the Corporation, whether voluntary or involuntary, the right to receive
        ratably all assets of the Corporation remaining after the payment to the
        holders of Preferred Stock of any amount which such holders are entitled
        to receive in preference to the holders of Common Stock upon such
        liquidation, dissolution or winding up of the Corporation, as provided
        in any Certificate of Designations, Powers, Preferences and Rights of
        the Preferred Stock adopted by the Board of Directors, and subject to
        any right the Preferred Stock may have to participate in the
        distribution of such assets as provided in any Certificate of
        Designations, Powers, Preferences and Rights of the Preferred Stock.

                2. VOTING. Each share of Common Stock shall entitle the holder
        thereof to one vote, in person or by proxy, together with Class A Common
        Stock at any and all meetings of the stockholders of the Corporation, on
        all propositions before such meetings.

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        SUBDIVISION C. CLASS A COMMON STOCK.

                1. DIVIDENDS AND LIQUIDATION. Subject to those rights expressly
        granted to the holders of Preferred Stock, the holders of Class A Common
        Stock shall have (a) the right to receive, together with the holders of
        Common Stock, dividends, when and as declared by the Board of Directors
        of the Corporation for the holders of Common Stock out of the assets of
        the Corporation available for the payment of dividends under the laws of
        the State of Delaware; provided, however, that in determining the amount
        of the dividends payable to the holders of Common Stock and the holders
        of Class A Common Stock in the event of any such declaration, holders of
        Class A Common Stock shall be entitled to the amount of dividends to
        which they would have been entitled had the conversion of Class A Common
        Stock into Common Stock described below taken place immediately prior to
        such declaration; and (b) upon any liquidation (complete or partial),
        dissolution or winding up of the Corporation, whether voluntary or
        involuntary, the right to receive, together with the holders of Common
        Stock, all assets of the Corporation remaining after the payment to the
        holders of Preferred Stock of any amount which such holders are entitled
        to receive in preference to the holders of Common Stock and Class A
        Common Stock upon such liquidation, dissolution or winding up of the
        Corporation, as provided in any Certificate of Designations, Powers,
        Preferences and Rights of the Preferred Stock adopted by the Board of
        Directors, and subject to any right the Preferred Stock may have to
        participate in the distribution of such assets as provided in any
        Certificate of Designations, Powers, Preferences and Rights of the
        Preferred Stock; provided, however, that in determining the amount of
        assets to be received by the holders of Common Stock and the holders of
        Class A Common Stock in the event of any such liquidation, dissolution
        or winding up of the Corporation, holders of Class A Common Stock shall
        be entitled to the amount of assets to which they would have been
        entitled had the conversion of Class A Common Stock into Common Stock
        described below taken place immediately prior to such liquidation,
        dissolution, or winding up of the Corporation.

                2. VOTING. Each share of Class A Common Stock shall entitle the
        holder thereof to vote, in person or by proxy, together with Common
        Stock at any and all meetings of the stockholders of the Corporation, on
        all propositions before such meetings. In any such vote, the holders of
        Class A Common Stock shall be entitled to that number of votes to which
        they would have been entitled had the conversion of Class A Common Stock
        into Common Stock described below taken place immediately prior to such
        vote; provided, however, that if at the time of any such vote no shares
        of Common Stock are outstanding, each share of Class A Common Stock
        shall entitle the holder thereof to one vote.

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                3. AUTOMATIC CONVERSION INTO COMMON STOCK. On the date that is
        one hundred eighty-one (181) days following the date of the final
        prospectus for a firmly underwritten public offering pursuant to an
        effective registration statement under the Securities Act of 1933, as
        amended, covering the offer and sale of Common Stock for the account of
        the Corporation, in which the gross proceeds to the Corporation (before
        underwriting discounts, commissions and fees) are at least $30,000,000
        (the "IPO"), each outstanding share of Class A Common Stock shall,
        without any further action by the Corporation or any holder of shares of
        Class A Common Stock, automatically convert into that number of shares
        of Common Stock set forth by the Board of Directors in a resolution
        adopted prior to the closing of the IPO, which resolution shall be filed
        with the Secretary of the Corporation and made available to any
        stockholder who so requests. The conversion ratio shall be set by the
        Board of Directors after having received the advice of the IPO
        underwriters as to the appropriate number of shares of Common Stock into
        which each share of Class A Common Stock should be converted."

        FURTHER RESOLVED, that the Certificate of Incorporation of the
Corporation be amended by deleting the first sentence of Article SIXTH as it now
exists and inserting in lieu thereof the following:

                "SIXTH: The number of directors of the Corporation which shall
        constitute the entire Board shall be not less than five (5) nor more
        than sixteen (16), with the exact number to be set by resolution adopted
        by a majority of the entire Board from time to time; provided, however,
        that the number of directors constituting the Board shall not be
        decreased by the Board of Directors below the number then in office
        unless such decrease shall become effective at any annual meeting of
        stockholders. The Board shall be divided into three classes, which are
        hereby designated Class I, Class II and Class III. The term of office of
        the Class I directors shall expire at the 2000 Annual Meeting of
        Stockholders; that of the Class II directors at the 2001 Annual Meeting
        of Stockholders; and that of the Class III directors at the 2002 Annual
        Meeting of Stockholders. At each annual meeting, directors to replace
        those whose terms expire at such annual meeting shall be elected to hold
        office until the third succeeding annual meeting. The directors shall be
        elected at the annual meeting of the stockholders and each director
        shall be elected to serve until his successor shall be elected and shall
        qualify."

        FURTHER RESOLVED, that the Certificate of Designation of Series A
Convertible Preferred Stock of the Corporation be amended by deleting Section
5(a) as it now exists and inserting in lieu thereof the following:

        "(a) Each share of this Series shall be convertible into 85.12 shares of
             Class A Common Stock, par value $.01 per share, of the Corporation
             (the "Conversion Amount"), at the option of the

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             holder thereof at any time that the holder elects to convert the
             Corporation's 7.5% Convertible Subordinated Debenture due August
             15, 2001 (the "Debenture") issued as a unit with such share."

        IN WITNESS WHEREOF, the Corporation has caused this Certificate to be
executed this ____ day of October, 1999.

                                       ILLUMINET HOLDINGS, INC.

                                       By:
                                          --------------------------------------
                                       Name: Roger H. Moore
                                       Title: President & CEO