Exhibit 4.12

                                                      Certificate Number _______

                         ________ UNDERWRITER WARRANTS

                              TO PURCHASE UNITS OF

                              YM BIOSCIENCES INC.

      THIS CERTIFIES THAT, for value received, [NAME] (the "HOLDER") is the
registered holder of o underwriter warrants (each an "UNDERWRITER WARRANT" and
collectively, the "UNDERWRITER WARRANTS"). Each Underwriter Warrant shall
entitle the Holder, subject to the terms and conditions set forth in this
certificate or by a replacement certificate (in either case, this "UNDERWRITER
WARRANT CERTIFICATE"), to acquire from YM BioSciences Inc. (the "COMPANY") one
unit (the "UNIT"), consisting of one (1) fully paid and non-assessable common
share of the Company (a "COMMON SHARE") and one-half of one (1/2) common share
purchase warrant (each whole common share purchase warrant a "WARRANT") at any
time commencing on the date hereof and continuing up to 5:00 p.m. (Toronto time)
on September 30, 2007 (the "TIME OF EXPIRY") on payment of Cdn.$3.15 per Unit
(the "EXERCISE PRICE"). The Warrants issuable upon exercise of the Underwriter
Warrants shall be issued pursuant to a warrant indenture dated September 30,
2004 between the Company and CIBC Mellon Trust Company. The number of Common
Shares (but not the number of Warrants) which the Holder is entitled to acquire
upon exercise of the Underwriter Warrants and payment of the Exercise Price are
subject to adjustment as hereinafter provided.

1.    EXERCISE OF UNDERWRITER WARRANTS.

1.1   ELECTION TO PURCHASE.

      The rights evidenced by this Underwriter Warrant Certificate may be
exercised by the Holder in whole or in part at any time commencing on the date
hereof and continuing up to the Time of Expiry and in accordance with the
provisions hereof by providing to the Company at 5045 Orbitor Drive, Building
11, Suite 400, Mississauga, Ontario, L4W 4Y4, Attention: Len Vernon, fax no.
(905) 629-4959 (or such other address in Canada as may be notified in writing by
the Company) (i) a duly completed and executed election to exercise form in
substantially the form attached as Exhibit "1" hereto ("ELECTION TO EXERCISE")
and (ii) payment of the Exercise Price by a certified cheque, bank draft or
money order payable at par to the order of YM BioSciences Inc., or by wire or
electronic funds transfer to an account designated by the Company, in each case
in the amount of the aggregate Exercise Price for the number of Units specified
in the Election to Exercise. A duly completed and executed Election to Exercise
shall be deemed to be delivered only upon personal delivery thereof to, or if
sent by mail or other means of transmission upon actual receipt thereof by, the
Company. If the Holder subscribes for a lesser number of Units than may be
subscribed for pursuant to the Underwriter Warrant Certificate, the Holder shall
be entitled to receive, without charge to the Holder, a new Underwriter Warrant
Certificate in respect of the balance of the Units referred to in any
surrendered Underwriter Warrant Certificate but not subscribed for.
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                                      -2-


1.2   EXERCISE.

      The Company shall, as soon as possible following the date of receipt of a
duly executed Election to Exercise and the Exercise Price for the number of
Units specified in the Election to Exercise (the "EXERCISE DATE"), issue as of
the Exercise Date that number of Common Shares comprising part of the Units
specified in the Election to Exercise as fully paid and non-assessable common
shares in the capital of the Company, and issue as of the Exercise Date that
number of Warrants comprising part of the Units specified in the Election to
Exercise as binding obligations of the Company.

1.3   CERTIFICATES.

      As promptly as practicable after the Exercise Date and, in any event,
within three business days of receipt of the Election to Exercise, the Company
shall issue and deliver to the Holder, registered in the name of the Holder, at
the address specified therein, or, if not so specified in the Election to
Exercise, cause to be held for pick up by the Holder at the address of the
Company as set out in subsection 1.1 (or at such additional place as may be
decided by the Company from time to time), certificates for the Common Shares
and Warrants comprising the Units specified in the Election to Exercise. The
Common Shares and Warrants issuable upon the exercise of the Underwriter
Warrants shall be deemed to have been issued and the person or persons to whom
such Common Shares and Warrants are to be issued shall be deemed to have become
the holder or holders of record of such Common Shares and Warrants on the
Exercise Date.

1.4   FRACTIONAL COMMON SHARE OR WARRANTS.

      Fractional Common Shares or Warrants shall not be issued upon the exercise
of any Underwriter Warrants (provided that, for greater certainty, the number of
Underwriter Warrants being exercised at any one time shall be aggregated to
determine the number of whole Warrants issuable upon such exercise). The Holder
shall not be entitled to any compensation or other right in lieu of fractional
Common Share or Warrants, as the case may be.

2.    ANTI-DILUTION PROTECTION.

2.1   DEFINITIONS.

      For the purposes of Section 2 the words and terms defined below shall have
the respective meanings specified therefor in this Subsection 2.1:

      (i)   "AIM" means the Alternative Investment Market of the London Stock
            Exchange plc.

      (ii)  "AMEX" means the American Stock Exchange;

      (iii) "DIVIDENDS PAID IN THE ORDINARY COURSE" means cash dividends
            declared payable on the Common Shares in any fiscal year of the
            Company to the extent that such cash dividends do not exceed, in the
            aggregate, the greater of: (i) 200% of the aggregate amount of cash
            dividends declared payable by the Company on the Common Shares in
            its immediately preceding fiscal year; (ii) 200% of the arithmetic
            mean of the aggregate amounts of cash dividends declared payable by
            the Company on the Common Shares in its three immediately preceding
            fiscal years; and (iii) 100% of the aggregate consolidated net
            income of the Company, before extraordinary items, for its
            immediately preceding fiscal year (such consolidated net income to
            be computed in accordance with Canadian generally accepted
            accounting principles);
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                                      -3-


      (iv)  "CURRENT MARKET PRICE PER COMMON SHARE", at any date, means the
            weighted average price per Common Share at which the Common Shares
            have traded on the TSX (or, if the Common Shares are not so listed,
            then on AMEX, or if the Common Shares are not then listed on the TSX
            or AMEX, then on AIM, or if the Common Shares are not then listed on
            the TSX, AMEX or AIM, the recognized stock exchange on which the
            Common Shares are listed on which the greatest volume of Common
            Shares were traded during the period referenced below or, if the
            Common Shares are not so listed on any recognized stock exchange,
            then on the over-the-counter market on which the Common Shares are
            traded as selected by action of the directors acting reasonably for
            such purpose), during the 20 most recent trading days ending on the
            fifth trading day before such date on which there has occurred at
            least one trade of at least one board lot of Common Shares prior to
            such date, such weighted average price to be determined by dividing
            the aggregate sale price of all Common Shares sold in board lots on
            such exchange or market, as the case may be, during the said 20
            trading days, by the number of Common Shares so sold;

      (v)   "DIRECTOR" means a director of the Company for the time being and
            reference herein to an "ACTION BY THE DIRECTORS" means an action by
            the directors of the Company as a board or, whenever duly empowered,
            an action by a committee of directors;

      (vi)  "RECOGNIZED STOCK EXCHANGE" means a stock exchange or quotation
            system recognized by the Canadian Securities Administrators; and

      (vii) "TSX" means the Toronto Stock Exchange.

2.2   ADJUSTMENTS.

      The Exercise Price and the number of Common Shares which may be subscribed
for upon exercise of the Underwriter Warrants shall be subject to adjustment
from time to time upon the occurrence of any of the events and in the manner
provided as follows:

      (a)   If and whenever at any time prior to the Time of Expiry, the Company
            shall:

            (i)   declare a dividend or make a distribution on its Common Shares
                  payable in Common Shares (or securities exchangeable for or
                  convertible into Common Shares), other than Dividends Paid in
                  the Ordinary Course; or
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                                      -4-


            (ii)  subdivide or change its outstanding Common Shares into a
                  greater number of Common Shares; or

            (iii) reduce, combine or consolidate its outstanding Common Shares
                  into a lesser number or Common Shares,

            (any of such events in these subclauses (i), (ii) and (iii) above
            being called a "SHARE REORGANIZATION"), then effective immediately
            after the record date or effective date, as the case may be, at
            which the holders of Common Shares are determined for the purposes
            of the Share Reorganization the Exercise Price shall be adjusted to
            a price determined by multiplying the applicable Exercise Price in
            effect on such effective date or record date by a fraction, the
            numerator of which shall be the number of Common Shares outstanding
            on such effective date or record date before giving effect to such
            Share Reorganization and the denominator of which shall be the
            number of Common Shares outstanding immediately after giving effect
            to such Share Reorganization (including, in the case where
            securities exchangeable for or convertible into Common Shares are
            distributed, the number of additional Common Shares that would have
            been outstanding had such securities been exchanged for or converted
            into Common Shares immediately after giving effect to such Share
            Reorganization).

      (b)   If and whenever at any time prior to the Time of Expiry the Company
            shall fix a record date for the issuing of rights, options or
            warrants to all or substantially all of the holders of the Common
            Shares entitling them for a period expiring not more than 45 days
            after such record date (the "RIGHTS PERIOD") to subscribe for or
            purchase Common Shares (or securities convertible into or
            exchangeable for Common Shares) at a price per share (or having a
            conversion or exchange price per share) which is less than 95% of
            the Current Market Price per Common Share on the record date for
            such issue (any of such events being called a "RIGHTS OFFERING"),
            then effective immediately after the end of the Rights Period the
            Exercise Price shall be adjusted to a price determined by
            multiplying the applicable Exercise Price in effect at the end of
            the Rights Period by a fraction the numerator of which shall be the
            sum of:

            (i)   the number of Common Shares outstanding as of the record date
                  for the Rights Offering; and

            (ii)  a number determined by dividing (A) either (i) the product of
                  the number of Common Shares issued during the Rights Period
                  upon exercise of the rights, warrants or options under the
                  Rights Offering and the price at which such Common Shares are
                  issued, or (ii) as the case may be, the product of the number
                  of Common Shares for or into which the convertible or
                  exchangeable securities issued during the Rights Period upon
                  exercise of the rights, warrants or options under the Rights
                  Offering are exchangeable or convertible and the exchange or
                  conversion price of the convertible or exchangeable securities
                  so issued, by (B) the Current Market Price per Common Share as
                  of the record date for the Rights Offering, and
<PAGE>
                                      -5-


            the denominator of which shall be the number of Common Shares
            outstanding (including the number of Common Shares actually issued
            or subscribed for during the Rights Period upon exercise of the
            rights, warrants or options under the Rights Offering) or which
            would be outstanding upon the conversion or exchange of all
            convertible or exchangeable securities issued during the Rights
            Period upon exercise of the rights, warrants or options under the
            Rights Offering, as applicable, in each case after giving effect to
            the Rights Offering.

            In order to give effect to the provisions of clause 2.2(e) in the
            circumstances described below, any Holder who shall have exercised
            his right to purchase Units during the period beginning immediately
            after the record date for a Rights Offering and ending on the last
            day of the Rights Period therefor, in addition to the Units to which
            he is otherwise entitled upon such exercise, shall be entitled to
            that number of additional Common Shares equal to the result obtained
            when the difference, if any, between the Exercise Price per Unit in
            effect immediately prior to the end of such Rights Offering and the
            Exercise Price per Unit, as adjusted for such Rights Offering
            pursuant to this clause 2.2(b), is multiplied by the number of Units
            purchased upon exercise of the Underwriter Warrant held by such
            holder during such period, and the resulting product is divided by
            the Exercise Price per Unit, as adjusted for such Rights Offering
            pursuant to this clause 2.2(b). Such additional Common Shares shall
            be deemed to have been issued to the Holder immediately following
            the end of the Rights Period and a certificate for such additional
            Common Shares shall be delivered to such Holder within 10 business
            days following the end of the Rights Period.

      (c)   If and whenever at any time prior to the Time of Expiry the Company
            shall fix a record date for the payment, issue or distribution to
            all or substantially all of the holders of the Common Shares of (i)
            a dividend, (ii) cash or assets (including evidences of the
            Company's indebtedness), or (iii) rights or other securities
            (including without limitation, securities convertible into or
            exchangeable for Common Shares), and such payment, issue or
            distribution does not constitute a Dividend Paid in the Ordinary
            Course, a Share Reorganization or a Rights Offering (any of such
            non-excluded events being herein called a "SPECIAL Distribution"),
            the Exercise Price shall be adjusted effective immediately after
            such record date to a price determined by multiplying the applicable
            Exercise Price in effect on such record date by a fraction:

            (i)   the numerator of which shall be:

                  (1)   the product of the number of Common Shares outstanding
                        on such record date and the Current Market Price per
                        Common Share on such record date; less
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                                      -6-


                  (2)   the fair market value, as determined by action of the
                        directors (whose determination shall be conclusive) and
                        subject to the prior approval of the TSX and any other
                        stock exchange or market on which the Common Shares may
                        be listed or traded, to the holders of the Common Shares
                        of such dividend, cash, assets, rights or securities so
                        paid, issued or distributed less the fair market value,
                        as determined by action of the directors (whose
                        determination shall be conclusive) and subject to the
                        prior approval of the TSX and any other stock exchange
                        or market on which the Common Shares may be listed or
                        traded, of the consideration, if any, received therefor
                        by the Company, and

            (ii)  the denominator of which shall be the number of Common Shares
                  outstanding on such record date multiplied by the Current
                  Market Price per Common Share on such record date.

            Such adjustment shall be made successively whenever such a record
            date is fixed. To the extent that such payment, issuance or
            distribution is not so made, the Exercise Price shall be readjusted
            effective immediately to the Exercise Price which would then be in
            effect based upon such payment, issuance or distribution actually
            made.

      (d)   If and whenever at any time prior to the Time of Expiry there shall
            be a reorganization, reclassification or other change of Common
            Shares at any time outstanding or change of the Common Shares into
            other shares or into other securities (other than a Share
            Reorganization), or a consolidation, amalgamation, arrangement or
            merger of the Company with or into any other corporation or other
            entity, or a transfer of all or substantially all of the undertaking
            or assets of the Company to another corporation or entity in which
            the holders of Common Shares are entitled to receive shares, other
            securities or property, including cash, (any of such events being
            herein called a "CAPITAL REORGANIZATION"), any Holder who exercises
            his right to subscribe for and purchase Units pursuant to the
            exercise of Underwriter Warrants after the effective date of such
            Capital Reorganization shall be entitled to receive, and shall
            accept for the same aggregate consideration in lieu of the number of
            Common Shares comprising part of the Units to which such Holder was
            theretofore entitled upon such exercise, the aggregate number of
            shares, other securities or other property, including cash, which
            such Holder would have received as a result of such Capital
            Reorganization had he exercised his right to acquire Units
            immediately prior to the effective date or record date, as the case
            may be, of the Capital Reorganization and had he been the holder of
            such Common Shares on such effective date or record date, as the
            case may be, subject to adjustment thereafter in accordance with
            provisions the same, as nearly as may be possible, as those
            contained in clauses 2.2(b) and 2.2(c); provided that in the event
            of such a consolidation, amalgamation, arrangement or merger of the
            Company with or into any other corporation or other entity resulting
<PAGE>
                                      -7-


            in the acquisition of more than one-half of the voting or equity
            interests of the Company, or a transfer of all or substantially all
            of the undertaking or assets of the Company, if a Holder does not
            exercise his right to subscribe for and purchase Units pursuant to
            the exercise of Underwriter Warrants, such Holder shall be entitled
            to exchange his Underwriter Warrants for replacement warrants of the
            acquiring corporation or other entity, exercisable for the unexpired
            term of the Underwriter Warrants, in number and having such terms
            and conditions including exercise price, as are necessary to (as
            nearly as practicable) ensure they are economically equivalent to
            the Underwriter Warrants at the effective date of any such
            transaction. If determined appropriate by the directors, acting
            reasonably, appropriate adjustments shall be made as a result of any
            such Capital Reorganization in the application of the provisions set
            forth in this subsection 2.2, with respect to the rights and
            interests thereafter of a Holder to the end that the provisions set
            forth in this subsection 2.2 shall thereafter correspondingly be
            made applicable as nearly as may reasonably be in relation to any
            shares, other securities or other property, including cash,
            thereafter deliverable upon the exercise of any Underwriter Warrant.
            Any such adjustments shall be made by and set forth in an agreement
            supplemental hereto approved by action by the directors, acting
            reasonably, and shall for all purposes be conclusively deemed to be
            appropriate adjustments.

      (e)   If and whenever at any time prior to the Time of Expiry there shall
            occur a Share Reorganization, a Rights Offering or a Special
            Distribution and any such event results in an adjustment to the
            Exercise Price pursuant to the provisions of this subsection 2.2 the
            number of Common Shares purchaseable as part of the Units (at the
            adjusted Exercise Price) upon the exercise of Underwriter Warrants
            shall be adjusted contemporaneously with the adjustment of the
            Exercise Price by multiplying the number of Common Shares
            theretofore purchaseable on the exercise thereof by a fraction, the
            numerator of which shall be the applicable Exercise Price in effect
            immediately prior to such adjustment and the denominator of which
            shall be the applicable Exercise Price resulting from such
            adjustment.

      (f)   In case the Company after the date of issue of the Underwriter
            Warrants shall take any action affecting the Common Shares, other
            than action described above in this subsection 2.2 which in the
            opinion of the directors, acting reasonably, would materially
            adversely affect the rights of the Holder, the Exercise Price or the
            number of Common Shares purchaseable as part of the Units upon
            exercise shall be adjusted in such manner, if any, and at such time,
            by action by the directors, acting reasonably, as they may determine
            to be equitable in the circumstances, but subject in all cases to
            any necessary regulatory approval.
<PAGE>
                                      -8-


2.3   RULES.

      For the purposes of subsection 2.2 hereof, any adjustment shall be made
successively whenever an event referred to therein shall occur, subject to the
following provisions:

      (a)   all calculations shall be made to the nearest 1/100th of a Common
            Share;

      (b)   no adjustment to an Exercise Price shall be required unless such
            adjustment would result in a change of at least 1% in the prevailing
            Exercise Price and no adjustment in the number of Common Shares
            purchasable as part of the Units upon exercise of the Underwriter
            Warrants will be required to be made unless the cumulative effect of
            such adjustment or adjustments would change the number of Common
            Shares purchasable as part of the Units upon the exercise of an
            Underwriter Warrant by at least one one-hundredth of a Common Share
            and, for greater clarity, any adjustment which, except for the
            qualification of this section, would otherwise have been required to
            be made shall be carried forward and taken into account in any
            subsequent adjustment; provided, however, that in no event shall the
            Company be obligated to issue fractional Common Shares or fractional
            interests in Common Shares upon exercise of an Underwriter Warrant
            or pay any amount in cash in lieu of issuing fractional Common
            Shares;

      (c)   if a dispute shall at any time arise with respect to adjustments to
            the Exercise Price or the number of Common Shares purchaseable as
            part of the Units pursuant to the exercise rights represented by an
            Underwriter Warrant, such disputes shall be conclusively determined
            by the Company's auditors or, if they are unable or unwilling to
            act, by such other firm of independent chartered accountants as may
            be selected by action by the directors and any such determination,
            shall be conclusive evidence of the correctness of any adjustments
            made; and

      (d)   if the Company shall set a record date to determine the holders of
            its Common Shares for the purpose of entitling them to receive any
            dividend or distribution or any subscription or purchase rights,
            options or warrants and shall thereafter and before the distribution
            to such shareholders of any such dividend, distribution or
            subscription or purchase rights legally abandon its plan to pay or
            deliver such dividend, distribution or subscription or purchase
            rights, then no adjustment in the Exercise Price or the number of
            Common Shares purchaseable as part of the Units upon exercise of the
            Underwriter Warrants shall be required by reason of the setting of
            such record date.

2.4   TAKING OF ACTIONS.

      As a condition precedent to the taking of any action which would require
an adjustment pursuant to Section 2.2 hereof, the Company shall take any action
that may, in the opinion of counsel, be necessary in order that the Company may
validly and legally issue as fully paid and non-assessable all of the Common
Shares comprising part of the Units which the Holder is entitled to receive in
accordance with the provisions of this Underwriter Warrant Certificate.

2.5   NOTICE.

      At least seven days prior to the effective date or record date, as the
case may be, of any event that requires or that may require an adjustment in any
of the exercise rights of the Holder under this Underwriter Warrant Certificate,
<PAGE>
                                      -9-


including the number of Common Shares that may be acquired as part of the Units
under this Underwriter Warrant Certificate, the Company shall deliver to the
Holder a certificate of the Company specifying the particulars of such event
and, if determinable, the required adjustment and the computation of such
adjustment. In case any adjustment for which a certificate has been given is not
then determinable, the Company shall promptly after such adjustment is
determinable deliver to the Holder a certificate of the Company showing how such
adjustment was computed. The Company hereby covenants and agrees that the
register of transfers and share transfer books for the Common Shares shall be
open during normal business hours for inspection by the Holder, and that the
Company will not take any action which might deprive the Holder of the
opportunity of exercising the rights of subscription contained in this
Underwriter Warrant Certificate, during such seven day period.

3.    SHARES TO BE RESERVED.

      The Company will at all times reserve and keep available out of its
authorized Common Shares, solely for the purpose of issue upon the exercise of
the Underwriter Warrants, such number of Common Shares as are then issuable upon
the exercise of the Underwriter Warrants and such number of Common Shares as are
then issuable upon the exercise of Warrants issuable as part of the Units
issuable upon exercise of the Underwriter Warrants. The Company covenants and
agrees that all Common Shares that are so issuable will, upon issuance, be duly
authorized fully paid and non-assessable. The Company will take such actions as
may be reasonably necessary and as are within its power to ensure that all such
Common Shares may be so issued without violation of any applicable laws or the
applicable requirements of any stock exchange upon which the Common Shares of
the Company may be listed.

4.    NO TRANSFER OF UNDERWRITER WARRANT.

      The Underwriter Warrants evidenced hereby are non-assignable,
non-transferable and non-negotiable and may not be exercised by or for the
benefit of any person other than the Holder.

5.    REPLACEMENT.

      Upon receipt of evidence satisfactory to the Company of the loss, theft,
destruction or mutilation of this Underwriter Warrant Certificate and, if
requested by the Company, upon delivery of an indemnity and/or surety bond in
amount and form satisfactory to the Company (or, in the case of mutilation, upon
surrender of this Underwriter Warrant Certificate), the Company shall issue and
deliver to the Holder a replacement certificate containing the same terms and
conditions as this Underwriter Warrant Certificate.

6.    EXPIRY DATE.

      The Underwriter Warrants shall expire and all rights to purchase Units
hereunder shall cease and become null and void at 5:00 p.m. (Toronto time) on
September 30, 2007.
<PAGE>
                                      -10-


7.    TIME.

      Time shall be of the essence of this Underwriter Warrant Certificate.

8.    BUSINESS DAY.

      In the event that any day on or before which any action is required or
permitted to be taken hereunder is not a business day, such action shall be
required or permitted to be taken on or before the requisite time on the next
succeeding day that is a business day.

9.    GOVERNING LAW.

      This Underwriter Warrant shall be governed by and construed and enforced
in accordance with the laws of the Province of Ontario and the federal laws of
Canada applicable therein and shall be treated in all respects as an Ontario
contract.

10.   SUCCESSOR.

      The Company shall not enter into any transaction whereby all or
substantially all of its undertaking, property and assets would become the
property of any other Company (herein called a "SUCCESSOR COMPANY") whether by
way of reorganization, reconstruction, consolidation, amalgamation, merger,
transfer, sale, disposition or otherwise, unless prior to or contemporaneously
with the consummation of such transaction the Company and the Successor Company
shall have executed such instruments and done such things as, in the opinion of
counsel to the Holder, acting reasonably, consider to be necessary or advisable
to establish that upon the consummation of such transaction:

      (a)   the Successor Company will have assumed all the covenants and
            obligations of the Company under this Underwriter Warrant
            Certificate, and

      (b)   this Underwriter Warrant Certificate will be a valid and binding
            obligation of the Successor Company entitling the Holder, as against
            the Successor Company, to all the rights of the Holder under this
            Underwriter Warrant Certificate.

      Whenever the conditions of this Section 9 shall have been duly observed
and performed, the Successor Company shall possess, and from time to time may
exercise, each and every right and power of the Company under this Underwriter
Warrant Certificate in the name of the Company or otherwise and any act or
proceeding by any provision hereof required to be done or performed by any
director or officer of the Company may be done and performed with like force and
effect by the like directors or officers of the Successor Company.

11.   GENERAL.

      This Underwriter Warrant Certificate is not valid for any purpose
whatsoever unless and until it has been signed by or on behalf of the Company.
The holding of the Underwriter Warrants evidenced by this Underwriter Warrant
Certificate shall not be construed as conferring upon the Holder any right or
interest whatsoever as a shareholder of the Company nor entitle the Holder to
any right or interest in respect thereof except as expressly provided in this
Underwriter Warrant Certificate.
<PAGE>
                                      -11-


                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]
<PAGE>

      IN WITNESS WHEREOF the Company has caused this Underwriter Warrant
Certificate to be signed by a duly authorized officer.

      DATED as of the    day of September, 2004.

                                       YM BIOSCIENCES INC.


                                       Per:
                                              ----------------------------------
                                               Name:
                                               Title:
<PAGE>

                                   EXHIBIT 1

                             ELECTION TO EXERCISE

      The undersigned hereby irrevocably elects to exercise the number of
Underwriter Warrants of [INSERT NAME OF HOLDER] set out below for the number of
Common Shares and Warrants (or other property or securities subject thereto) as
set forth below:

            (i)   Number of Underwriter Warrants to be exercised: ______________

            (ii)  Number of Units (one Share and one-half of one Warrant per
                  Unit) to be acquired: ______________

            (iii) Exercise Price per Underwriter Warrant: Cdn.$3.15

            (iv)  Aggregate Purchase Price [(ii) multiplied by (iii)]: $________

and hereby tenders a certified cheque, bank draft or cash, or immediately
available funds by wire or electronic funds transfer, for such aggregate
purchase price, and directs such Common Shares and Warrants to be registered and
certificates therefor to be issued as directed below.


            DATED this ______ day of _________________, 200__.



                                      [INSERT NAME OF HOLDER]


                                      Per:____________________________________

Direction as to Registration

Name of Registered Holder:               _____________________________________

Address of Registered Holder:            _____________________________________

                                         _____________________________________

                                         _____________________________________