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                                                                    Exhibit 10.4

                         THIRD WAVE TECHNOLOGIES, INC.
                        1998 INCENTIVE STOCK OPTION PLAN


1.   Purpose. The purpose of the Third Wave Technologies, Inc. 1998 Incentive
     Stock Option Plan (the "Plan") is to encourage certain employees of Third
     Wave Technologies, Inc. (the "Corporation") to acquire or increase their
     stock ownership in the Corporation, and to enable the Corporation to
     attract and retain personnel necessary for continued growth and
     profitability.

2.   Effective Date and Term of Plan. The Plan shall become effective on the
     date adopted by the Board of Directors of the Corporation ("Board of
     Directors") and shall continue for a period of ten years unless sooner
     terminated as provided in Paragraph 17.

3.   Approval of Shareholders. The Plan is subject to the approval of holders of
     a majority of all of the outstanding voting shares of the Corporation. If
     it is not so approved on or before one year after the date of adoption of
     the Plan by the Board of Directors, the Plan shall not come into effect and
     any options granted pursuant to the Plan shall be deemed canceled. No
     option may be exercised prior to approval of the Plan by the shareholders.

4.   Stock Subject to Plan. Only Common Stock, with $1.00 par value per share,
     of the Corporation ("Common Stock") may be issued pursuant to options
     granted under this Plan. The maximum number of shares of Common Stock that
     may be issued pursuant to the exercise of options granted under the Plan
     ("Options") is Three Hundred Fifty (350) shares, subject to any adjustments
     provided in Paragraph 16. If any Options expire or terminate for any reason
     without having been exercised in full, the unpurchased shares subject
     thereto shall again be available for further grants under the Plan.

5.   Administration. The Plan shall be administered by the committee described
     in Paragraph 6 (the "Committee"). Subject to the express provisions of the
     Plan, the Committee shall have complete authority in its discretion, to
     determine those employees ("Participants") to whom Options shall be
     granted, the option price, the option periods and the number of shares to
     be subject to each Option. Subject to the express provisions of the Plan,
     the Committee shall also have the authority in its discretion to prescribe
     the time or times at which Options may be exercised, the limitations upon
     the exercise of Options (including limitations effective upon death,
     disability or termination of employment of any Participant) and the
     restrictions, if any, to be imposed upon the transferability of shares
     acquired upon exercise of Options. In making such determinations, the
     Committee may take into account the nature of the services rendered by the
     respective Participants, their present and potential contributions to the
     success of the Corporation and such other factors as the Committee in its
     discretion shall deem relevant. Subject to the express provisions of the
     Plan, the Committee shall also have complete authority to interpret the
     Plan, to prescribe, amend and rescind rules and regulations relating to the
     Plan, to determine the terms and provisions of the respective option
     agreements (which need not be identical), to determine whether the shares
     delivered upon exercise of Options will be treasury shares or will be
     authorized but previously unissued share and to make all other
     determinations necessary or advisable for the administration of the Plan.
     The Committee's determinations on the matters referred to in this paragraph
     shall be conclusive.

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6.   Committee. The Committee shall consist of not less than three members of
     the Board of Directors who are not eligible, and have not at any time
     within one year prior to appointment to the Committee been eligible, to
     receive options under the Plan or any other plan of the Corporation
     entitling participants therein to acquire stock or stock options of the
     Corporation. The Committee shall be appointed from time to time by the
     Board of Directors, which may from time to time appoint members of the
     Committee in substitution for members previously appointed and may fill
     vacancies, however caused, in the Committee. A majority of its members
     shall constitute a quorum. All determinations of the Committee shall be
     made by a majority of its members. Any decision or determination reduced to
     writing and signed by all of the members shall be fully as effective as if
     it had been made by a majority vote at a meeting duly called and held. The
     Committee may hold meetings by use of conference telephone or similar
     communications equipment by which all persons participating in the meeting
     can hear each other.

7.   Eligibility. An Option may be granted under the Plan to any employee of the
     Corporation, and of its present and future subsidiaries, as defined in
     Section 424(f) of the Internal Revenue Code of 1986, as amended
     ("Subsidiaries"). The foregoing nonwithstanding, members of the Committee
     shall not, while serving as members of the Committee, be eligible to
     receive Options.

8.   Option Price. The option price per share will be determined by the
     Committee at the time each Option is granted, but shall not be less than
     100% of the fair market value, as determined by the Committee, of a share
     of Common Stock on the date of grant. If such Option is granted to a person
     who owns, directly or indirectly, stock possessing more than 10% of the
     total combined voting power of all classes of stock of the Corporation on
     the date of the grant, the option price per share shall not be less than
     110% of its fair market value.

9.   Option Periods. The term of each Option will be for such period not
     exceeding ten years from the date of grant, as the Committee shall
     determine; provided, however, that if such Option is granted to a person
     who owns, directly or indirectly, stock possessing more than 10% of the
     total combined voting power of all classes of stock of the Corporation on
     the date of the grant, the term of such Option shall not exceed five years
     from the date of grant. An Option shall be considered granted on the date
     of the Committee acts to grant the Option or such later date as the
     Committee shall specify. Each Option shall be subject to earlier
     termination as described under Paragraphs 13 and 17.

10.  Exercise of Options. Each Option may be exercised at any time during the
     option period for such Option (subject to the restrictions in this
     paragraph, in Paragraph 13 and in the agreements referred to in Paragraph
     14) by written notice delivered to an officer of the Corporation, stating
     the number of shares with respect to which the Option is being exercised.

11.  Payment for Option. Within five (5) business days following the date of
     exercise, the Participants shall make full payment of the option price (i)
     in cash; (ii) with the consent of the Committee, by tendering previously
     acquired shares of Common Stock (valued at their fair market value, as
     determined by the Committee, as of the date of exercise); or (iii) any
     combination of (i) and (ii). Shares of Common Stock tendered shall be duly
     endorsed in blank or accompanied by stock powers duly endorsed in blank.
     Upon receipt of the payment of the entire option price for the shares so
     purchased, certificates for such shares shall be delivered to the
     Participant. The transferability of such shares shall be subject to the


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        restrictions contained in the Shareholder Agreement dated as of July 29,
        1994, or as otherwise may be required by the Board of Directors from
        time to time, and the Participant agrees to execute such documents as
        may be required by the Corporation to become an "Agreeing Shareholder"
        as such term is defined in the Shareholder Agreement.

12.     Maximum Per Participant. The aggregate fair market value, as determined
        by the Committee, of the stock for which options held by a Participant
        are exercisable for the first time under the Plan or other options
        granted to the Participant under any plan of the Corporation or any
        Subsidiary during any calendar year shall not exceed $100,000. For
        purposes of this paragraph, the fair market value of stock subject to an
        Option or other Incentive Stock Option, as the case may be, is granted.

13.     Termination of Employment. Except as hereinafter provided, no Option may
        be exercised later than three months after a Participant terminates his
        employment with the Corporation or its Subsidiaries, as the case may be.
        If termination of employment results from the deliberate willful or
        gross misconduct of a Participant, then the Option shall be forfeited
        upon termination. If termination of employment results from the
        disability of a Participant within the meaning of Section 22(e)(3) of
        the Internal Revenue Code of 1986, as amended, any Option may be
        exercised at any time within twelve months after such termination of
        employment, but in no event beyond the option period. If termination of
        employment results from the death of a Participant, the personal
        representative of the Participant's estates, or a person who by bequest,
        inheritance, or otherwise by reason of the Participant's death, acquired
        the right to exercise the Option, may exercise any Option at any time
        within three years after the death of such Participant, but in no event
        beyond the option period. The Committee may impose additional
        restrictions upon the exercise of Options after termination of
        employment, including prohibition of such exercise.

14.     Agreements. Options granted pursuant to the Plan shall be evidenced by
        stock option agreements in such form as the Committee shall from time to
        time adopt.


15.     Nontransferability of Options. Options under the Plan are not
        transferable by a Participant other than by will or the laws of descent
        or distribution, and may be exercised during the lifetime of a
        Participant only by such Participant.

16.     Adjustment of Number of Shares. In the event of any change in the
        outstanding Common stock of the Corporation by reason of stock
        dividends, recapitalization, reorganization, mergers, consolidations,
        split-ups, combinations or exchanges of shares and the like, the
        Committee shall, consistent with such change, appropriately adjust the
        number and kind of shares which thereafter may be optioned and sold
        under the Plan, the number and kind of shares under option in
        outstanding and sold under the Plan, the number and kind of shares under
        option in outstanding stock option agreements and the purchase price per
        share thereof. The determination of the Committee as to any such
        adjustment shall be final and conclusive. No adjustment or substitution
        provided for in this paragraph shall require the Corporation in any
        stock option agreement to sell a fractional share and the total
        substitution or adjustment with respect to each stock option agreement
        shall be limited accordingly.

17.     Amendment, Suspension or Termination. The Board of Directors, without
        further approval of the shareholders, may from time to time amend,
        suspend or terminate the Plan in such respects as the Board may deem
        advisable; provided, however, that no amendment shall


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        become effective without prior approval of the shareholders which would
        (i) increase the aggregate number of shares which may be issued pursuant
        to Options granted under the Plan, except as permitted under Paragraph
        16; (ii) permit the granting of options to anyone other than an employee
        of the Corporation or a Subsidiary or to a member of the Committee;
        (iii) decrease the minimum option prices; (iv) increase the maximum
        option period; (v) increase the maximum option prices; (vi) extent the
        terms of the Plan. No amendment shall, without the Participant's
        consent, alter or impair any of the rights or obligations under any
        Option theretofore granted to the Participant.

Dated this 26th day of May, 1998.

THIRD WAVE TECHNOLOGIES, INC.

By: /s/ [Signature illegible]
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Attest: /s/ [Signature illegible]
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