Document:

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.
<PAGE>
                                      -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);
<PAGE>
                                      -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
<PAGE>
                                      -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
<PAGE>
                                      -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:            _____________________________________

                                         _____________________________________

                                         _____________________________________THIS WARRANT AND THE SECURITIES ISSUABLE UPON EXERCISE OF THIS WARRANT HAVE NOT
BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES
ACT"), OR THE SECURITIES LAWS OF ANY STATE. THE SECURITIES REPRESENTED HEREBY
ARE RESTRICTED AND MAY NOT BE SOLD, OFFERED FOR SALE, ASSIGNED, TRANSFERRED OR
OTHERWISE DISPOSED OF, UNLESS REGISTERED PURSUANT TO THE PROVISIONS OF THE
SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS OR AN OPINION OF COUNSEL,
ACCEPTABLE TO THE COMPANY, IS OBTAINED STATING THAT SUCH DISPOSITION IS IN
COMPLIANCE WITH AN AVAILABLE EXEMPTION FROM SUCH REGISTRATION.

Dated as of                                 , 2004           No. W
            --------------------------------                      -------------

                          21ST CENTURY HOLDING COMPANY

              (INCORPORATED UNDER THE LAWS OF THE STATE OF FLORIDA)

          REDEEMABLE WARRANT FOR THE PURCHASE OF SHARES OF COMMON STOCK

      FOR VALUE RECEIVED, 21st Century Holding Company, a Florida corporation
(the "Company"), hereby certifies that _________________________________, its
successors and assigns (the "Holder"), is the owner of such number of warrants
(the "Warrants") as set forth in Section 1 hereof. Each Warrant initially
entitles the Holder, subject to the provisions hereof, to purchase from the
Company at any time and from time to time on and after the date hereof until
5:00 p.m. Florida local time on the Expiration Date (as described in Section 3
herein), one fully paid and non-assessable share of Common Stock (as defined
below) at the Exercise Price per share of Common Stock (as described in Section
2 herein) on the terms and conditions hereinafter set forth.

      The term "Common Stock" means the Common Stock, par value $0.01 per share,
of the Company as constituted on the date hereof (the "Base Date"). The number
of shares of Common Stock to be received upon the exercise of this warrant
certificate may be adjusted from time to time as hereinafter set forth. The
shares of Common Stock deliverable upon such exercise, and as adjusted from time
to time, are hereinafter referred to as "Warrant Shares." The term "Other
Securities" means any other equity or debt securities that may be issued by the
Company in addition thereto or in substitution for the Warrant Shares. The term
"Company" means and includes the corporation named above as well as any
immediate successor corporation resulting from a reorganization.

      Upon receipt by the Company of documentation reasonably satisfactory to it
of the loss, theft, destruction or mutilation of this warrant certificate, and
(in the case of loss, theft or destruction) of reasonably satisfactory
indemnification, and upon surrender and cancellation of this warrant
certificate, if mutilated, the Company shall execute and deliver a new warrant
certificate of like tenor and date. Any such new warrant certificate executed
and delivered shall constitute an additional contractual obligation on the part
of the Company, whether or not this warrant certificate so lost, stolen,
destroyed or mutilated shall be at any time enforceable by anyone.

                                       1
<PAGE>

      The Holder agrees with the Company that this warrant certificate is
issued, and all the rights hereunder shall be held subject to, all of the
conditions, limitations and provisions set forth herein.

      1. NUMBER OF WARRANTS. The Holder is the owner of a number of warrants
equal to the aggregate principal amount of the 6% Senior Subordinated Notes the
Holder has purchased pursuant to the terms of the Unit Purchase Agreement (as
hereinafter defined) divided by the Exercise Price.

      2. EXERCISE PRICE. The Exercise Price shall equal 115% of the
weighted-average volume price for the Common Stock on Nasdaq as reported by
Bloomberg Financial Markets ("Bloomberg") for the 5 consecutive trading days
prior to the date of the Closing as set forth in the Unit Purchase Agreement;
provided, however, that in no event shall the Exercise Price be lower than
$12.75 per share.

      3. EXERCISE OF WARRANT. This warrant certificate may be exercised in whole
or in part, at any time, or from time to time during the period commencing on
the date hereof and expiring three years after the date hereof (the "Expiration
Date"). The Warrants must be exercised so as to purchase one full Warrant Share.

      4. NOTICE OF EXERCISE. Exercise of the Warrants shall be effected in any
such case by presentation and surrender of this warrant certificate to the
Company at its principal office, at the office of its stock transfer agent or
any other warrant agent designated by the Company (the "Warrant Agent") if any,
with the Warrant Exercise Form, a form of which is attached hereto as Exhibit A,
duly executed and accompanied by payment (either in cash or by certified or
official bank check, payable to the order of the Company) of the Exercise Price
for the number of Warrant Shares specified in such form and instruments of
transfer, if appropriate, duly executed by the Holder or its duly authorized
attorney. If this warrant certificate should be exercised in part only, the
Company shall, upon surrender of this warrant certificate for cancellation,
execute and deliver a new warrant certificate evidencing the rights of the
Holder thereof to purchase the balance of the Warrant Shares purchasable
hereunder. Upon receipt by the Company of this warrant certificate, together
with the Exercise Price, at its office, or by the Warrant Agent at its office,
in proper form for exercise, the Holder shall be deemed to be the Holder of
record of the shares of Common Stock issuable upon such exercise,
notwithstanding that the stock transfer books of the Company shall then be
closed or that certificates representing such shares of Common Stock shall not
then be actually delivered to the Holder. The Company shall pay any and all
documentary stamp or similar issue or transfer taxes payable in respect of the
issue or delivery of shares of Common Stock on exercise of this warrant
certificate, but in no event shall the Company be responsible or liable for
income taxes or transfer taxes upon the issuance or transfer of the Warrants or
the Warrant Shares.

      5. REDEMPTION RIGHTS. The Warrants may be redeemed, in whole or in part,
at any time or from time to time, at the Company's sole option, commencing a
year from the date hereof at a redemption price of $0.01 per Warrant Shares;
provided, however, that before any such call for redemption of the Warrants the
weighted-average volume price for the Company's Common Stock quoted on the
Nasdaq National Market ("Nasdaq") shall have for 20 consecutive trading days
ending not more than 10 days prior to the notice of redemption been in excess of
150% of the Exercise Price, as such may be adjusted from time to time.
Redemption of the Warrants may only occur upon 30 days' prior written notice to
the Holder, such notice to include certification of the trading price of the
Company's Common Stock on Nasdaq as reported by Bloomberg. If the Company
exercises its right to redeem the Warrants, in whole or in part, it shall mail a
notice of redemption to the Holder, first class, postage prepaid, not later than
the 30th day before the date fixed for redemption, at such Holder's last address
as shall appear on the records of the Company or the Company's Warrant Agent, if
any. Any notice mailed in the manner provided herein shall be conclusively
presumed to have been duly given whether or not the Holder receives such notice.
The notice of redemption shall specify the redemption price, the date fixed for
redemption, the place where the warrant certificate shall be delivered and the
redemption price shall be paid, and that the right to exercise the Warrants
shall terminate at 5:00 p.m. Florida local time on the business day immediately
preceding the date fixed for redemption. The date fixed for the redemption of
the Warrants shall be the Redemption Date. Any right to exercise a Warrant shall
terminate at 5:00 p.m. Florida local time on the business day immediately
preceding the Redemption Date. On and after the Redemption Date, the Holder
shall have no further rights except to receive, upon surrender of a certificate
evidencing Warrants duly endorsed or accompanied by a written instrument or
instruments of redemption in form satisfactory to the Company, the redemption
price of $0.01, without interest, per Warrant Shares.

                                       2
<PAGE>

      6. RESERVATION OF SHARES. The Company will at all times reserve for
issuance and delivery upon exercise of this warrant certificate all shares of
Common Stock or other shares of capital stock of the Company (and Other
Securities) from time to time receivable upon exercise of this warrant
certificate. All such shares (and Other Securities) shall be duly authorized
and, when issued upon such exercise, shall be validly issued, fully paid and
non-assessable and free of all preemptive rights.

      7. FRACTIONAL SHARES. No fractional shares or script representing
fractional shares shall be issued upon the exercise of the Warrants, but the
Company shall pay the Holder an amount equal to the fair market value of such
fractional share of Common Stock in lieu of each fraction of a share otherwise
called for upon any exercise of the Warrants, as determined by the Board of
Directors of the Company.

      8. EXCHANGE, TRANSFER, ASSIGNMENT OR LOSS OF WARRANT. This warrant
certificate is exchangeable, without expense, at the option of the Holder, upon
presentation and surrender hereof to the Company or at the office of its Warrant
Agent, if any, for other warrant certificates of different denominations,
entitling the Holder to purchase in the aggregate the same number of shares of
Common Stock purchasable hereunder. Upon surrender of this warrant certificate
to the Company or at the office of its Warrant Agent, if any, with an
appropriate form of assignment duly executed and funds sufficient to pay any
transfer tax, the Company shall, without charge, execute and deliver a new
warrant certificate in the name of the assignee named in such instrument of
assignment and this warrant certificate shall promptly be canceled. This warrant
certificate may be divided or combined with other warrant certificates that
carry the same rights upon presentation hereof at the office of the Company or
at the office of its Warrant Agent, if any, together with a written notice
specifying the names and denominations in which new warrant certificates are to
be issued and signed by the Holder hereof.

                                       3
<PAGE>

      9. RIGHTS OF THE HOLDER. The Holder shall not, by virtue hereof, be
entitled to any rights as a shareholder in the Company, either at law or in
equity, and the rights of the Holder are limited to those expressed in this
warrant certificate.

      10. ANTI-DILUTION PROVISIONS.

            10.1 ADJUSTMENT FOR RECAPITALIZATION. If the Company shall at any
time subdivide its outstanding shares of Common Stock (or Other Securities at
the time receivable upon the exercise of the Warrants) by recapitalization,
reclassification or split-up thereof, or if the Company shall declare a stock
dividend or distribute shares of Common Stock to its shareholders, the number of
shares of Common Stock subject to this warrant certificate immediately prior to
such subdivision shall be proportionately increased and the Exercise Price shall
be proportionately decreased, and if the Company shall at any time combine the
outstanding shares of Common Stock by recapitalization, reclassification or
combination thereof, the number of shares of Common Stock or Other Securities
subject to this warrant certificate immediately prior to such combination shall
be proportionately decreased and the Exercise Price shall be proportionately
increased. Any such adjustments pursuant to this Section 10.1 shall be effective
at the close of business on the effective date of such subdivision or
combination or if any adjustment is the result of a stock dividend or
distribution then the effective date of such adjustment based thereon shall be
the record date therefor.

            10.2 ADJUSTMENT FOR REORGANIZATION, CONSOLIDATION, MERGER, ETC. In
the case of a reorganization of the Company after the Base Date, the Holder,
upon the exercise thereof as provided in Section 1, at any time after the
consummation of such reorganization, shall be entitled to receive, in lieu of
the securities and property receivable upon the exercise of this warrant
certificate prior to such consummation, the securities or property to which such
Holder would have been entitled upon such consummation if such Holder had
exercised this warrant certificate immediately prior thereto; in each such case,
the terms of this warrant certificate shall be applicable to the securities or
property receivable upon the exercise of this warrant certificate after such
consummation.

            10.3 ISSUANCES BELOW EXERCISE PRICE. Except in the case of the
issuance of Common Stock issued (i) pursuant to any employee benefit plan of the
Company now existing or to be implemented in the future, (ii) for consideration
other than cash pursuant to a merger, consolidation, acquisition or similar
business combination, (iii) in connection with any transaction referred to in,
or contemplated by, this Section 10 hereof, (iv) pursuant to any equipment
leasing or loan arrangement, or debt financing from a bank or similar financial
or lending institution, (v) issued by the Company pursuant to a registration
statement filed under the Securities Act, or (v) issued in connection with
strategic transactions involving the Company and other entities, including (a)
joint ventures, manufacturing, marketing or distribution arrangements or (b)
technology transfer or development arrangements, if the Company at any time
while the Warrants are outstanding, shall issue shares of Common Stock at a
price per share (an "Issuance Price") less than the Exercise Price (or in the
case of an issuance of Common Stock in a private placement at less than 80% of
the Exercise Price), then the Exercise Price shall be multiplied by a fraction,
the numerator of which shall be the number of shares of Common Stock outstanding
immediately prior to the issuance of such Common Stock plus the number of shares
of Common Stock which the price paid for such shares of Common Stock would
purchase at the Exercise Price, and the denominator of which shall be the sum of
the number of shares of Common Stock outstanding immediately prior to such
issuance plus the number of shares of Common Stock so issued or issuable. Upon
each adjustment of the Exercise Price pursuant to the provisions of this Section
10.2, the number of Warrant Shares issuable upon the exercise of each Warrant
shall be adjusted by multiplying a number equal to the Exercise Price in effect
immediately prior to such adjustment by the number of Warrant Shares issuable
upon exercise of the Warrant immediately prior to such adjustment and dividing
the product so obtained by the adjusted Exercise Price.

                                       4
<PAGE>

            10.4 NOTICES OF RECORD DATE, ETC. In case:

                  (a) the Company shall take a record of the holders of its
Common Stock (or Other Securities at the time receivable upon the exercise of
the Warrants) for the purpose of entitling them to receive any dividend (other
than a cash dividend at the same rate as the rate of the last cash dividend
theretofore paid) or other distribution, or any right to subscribe for, purchase
or otherwise acquire any shares of stock of any class or any other securities,
or to receive any other right; or

                  (b) of any capital reorganization of the Company, any
reclassification of the capital stock of the Company, or any consolidation or
merger of the Company with or into another corporation; then, and in each such
case, the Company shall mail or cause to be mailed to the Holder at the time
outstanding a notice specifying, as the case may be, (i) the date on which a
record is to be taken for the purpose of such dividend, distribution or right,
and stating the amount and character of such dividend, distribution or right, or
(ii) the date on which such reorganization, reclassification, consolidation or
merger is to take place, and the time, if any, is to be fixed, as to which the
holders of record of Common Stock (or such Other Securities at the time
receivable upon the exercise of the Warrants) shall be entitled to exchange
their shares of Common Stock (or such Other Securities) for securities or other
property deliverable upon such reorganization, reclassification, consolidation
or merger. Such notice shall be mailed at least 20 days prior to the date
therein specified and the Warrants may be exercised prior to said date during
the term of the Warrants.

            10.5 LIMITATION ON ANTI-DILUTION ADJUSTMENTS. Notwithstanding
anything to the contrary contained herein, the Company shall not adjust the
number of Warrant Shares as provided in this Section 10, if such adjustment
would, either individually or together with one or more other adjustments or
together with one or more issuances of Transaction Shares (as defined in the
Unit Purchase Agreement dated as of ___________________, 2004 (the "Unit
Purchase Agreement") among the Company and the Purchasers named therein), cause
the issuance of shares of Common Stock to exceed the number of shares that the
Company could then issue under Section 4350(i) of the rules and regulations of
Nasdaq (the "Nasdaq Rules") or any successor rule or regulation. Under Section
4350(i) of the Nasdaq Rules, a company may not issue shares, and may not issue
securities convertible into shares, where the shares issued could in the
aggregate equal 20% or more of the voting power of the shares outstanding,
without obtaining shareholder approval. The foregoing limitation shall only
apply until such time as the Company obtains the requisite approval of its
shareholders for the issuance of the Transaction Shares, as required by Section
4350(i) of the Nasdaq Rules or any successor rule or regulation. The Company
covenants and agrees that it shall include a proposal for the approval of the
issuance of the Transaction Shares in the Company's proxy statement for its next
regular annual meeting of shareholders. If, due to the foregoing limitation, the
Company cannot adjust the Warrant Shares as provided in Section 10.3 above,
then, subject to NASD approval, the Company agrees that the Exercise Price
hereof shall be reduced to equal the Issuance Price(s) of the shares of Common
Stock that triggered the adjustment pursuant to Section 10.3.

                                       5
<PAGE>

      11. TRANSFER TO COMPLY WITH THE SECURITIES ACT. The Warrants and any
Warrant Shares or Other Securities may not be sold, transferred, pledged,
hypothecated or otherwise disposed of unless registered under the Securities Act
and any applicable state securities laws or pursuant to available exemptions
from such registration, provided that the transferor delivers to the Company an
opinion of counsel satisfactory to the Company confirming the availability of
such exemption.

      12. REGISTRATION RIGHTS. The Warrants and the Warrant Shares issuable upon
exercise of the Warrants shall be subject to certain registration rights as
provided in the registration rights agreement (the "Registration Rights
Agreement") among the Company and the initial holders of the Warrants. If the
Company fails to comply with the terms of the Registration Rights Agreement, the
Exercise Price shall be reduced by 10% for each full period of 30 consecutive
days of such non-compliance (and there shall be no pro rata reduction of the
Exercise Price if a period of non-compliance is not a full 30-day period).

      13. LEGEND. Unless the Warrant Shares or Other Securities have been
registered under the Securities Act, upon exercise of any of the Warrants and
the issuance of any of the Warrant Shares or Other Securities, all certificates
representing such securities shall bear on the face thereof substantially the
following legend:

            "The securities represented by this certificate have not been
            registered under the Securities Act of 1933, as amended (the "Act"),
            or under applicable state securities laws and may not be sold,
            offered for sale, assigned, transferred or otherwise disposed of,
            unless registered pursuant to the provisions of the Act and any
            applicable state securities laws or unless an opinion of counsel to
            the Company is obtained stating that such disposition is in
            compliance with an available exemption from such registration."

      14. NOTICES. All notices required hereunder shall be in writing and shall
be deemed given when sent by facsimile, delivered personally or within two days
after mailing when mailed by certified or registered mail, return receipt
requested, to the Company at its principal office, or to the Holder at the
address set forth on the record books of the Company, or at such other address
of which the Company or the Holder has been advised by notice hereunder.

                                       6
<PAGE>

      15. APPLICABLE LAW. The Warrants are issued under and shall for all
purposes be governed by and construed in accordance with the laws of the State
of Florida, without giving effect to the choice of law rules thereof.

      IN WITNESS WHEREOF, the Company has caused this warrant certificate to be
signed on its behalf, in its corporate name, by its duly authorized officer, all
as of the day and year first above written.

                                       21ST CENTURY HOLDING COMPANY,
                                       a Florida corporation

                                       By:
                                          --------------------------------------
                                          Richard A. Widdicombe,
                                          Chief Executive Officer

                                       7
<PAGE>

                                    EXHIBIT A

                              WARRANT EXERCISE FORM

(To be executed by the Holder to exercise the right to purchase shares of Common
Stock under the foregoing Warrant)

To 21st Century Holding Company:

      In accordance with the warrant certificate enclosed with this Warrant
Exercise Form, the undersigned hereby irrevocably elects to purchase________
shares of Common Stock, $0.01 par value per share ("Common Stock"), of 21st
Century Holding Company and, encloses herewith $__________ in cash, certified or
official bank check or checks, which sum represents the aggregate Exercise Price
(as defined in the Warrant) for the number of shares of Common Stock to which
this Warrant Exercise Form relates, together with any applicable taxes payable
by the undersigned pursuant to the warrant certificate.

      The undersigned requests that certificates for the shares of Common Stock
issuable upon this exercise be issued in the name of:

                                       PLEASE INSERT SOCIAL SECURITY OR
                                       TAX IDENTIFICATION NUMBER

                                       -----------------------------------------

--------------------------------------------------------------------------------
                         (Please print name and address)

      If the number of shares of Common Stock issuable upon this exercise shall
not be all of the shares of Common Stock that the undersigned is entitled to
purchase in accordance with the enclosed warrant certificate, the undersigned
requests that a new warrant certificate evidencing the right to purchase the
shares of Common Stock not issuable pursuant to the exercise evidenced hereby be
issued in the name of and delivered to:

--------------------------------------------------------------------------------
                         (Please print name and address)

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

Dated:
      -----------------------          -----------------------------------------
                                       (Print name of holder)

                                       By:
                                          --------------------------------------

                                       Name:
                                            ------------------------------------

                                       Title:
                                             -----------------------------------

                                       (Signature must conform in all respects
                                       to name of Holder as specified on the
                                       face of the Warrant)

                                        8

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