EXHIBIT 4.1
 
Rules of the Amgen Limited
Sharesave Plan

1.   Definitions

     In these Rules:

1.1  the following words and expressions have the following meanings:

     "Act"                          the Income and Corporation Taxes Act 1988;

     "Associated Company"           an associated company of the Company within
                                    the meaning of Section 187(2) of the Act;

     "Auditors"                     the auditors nominated by the Directors for
                                    the purposes of the Plan;

     "Bonus Date"                   the date on which a bonus becomes payable
                                    under the relevant Savings Contract after
                                    payment of 36 Savings Contributions;

     "Business Day"                 any day on which Shares may be dealt in on
                                    the U.S. NASDAQ Stock Market National Market
                                    system (or such other system exchange on
                                    which the shares are then traded);

     "Company"                      Amgen Limited;

     "Contractual Savings Scheme"   the arrangement specified for the time being
                                    by the Directors under which Savings
                                    Contributions are made by a Participant in
                                    accordance with the Plan, such arrangement
                                    being a certified contractual savings scheme
                                    within the meaning of Section 326 of the Act
                                    which has been approved by the Commissioners
                                    of Inland Revenue for the purposes of
                                    Schedule 9 to the Act;

     "Control"                      the meaning given to that expression in
                                    Section 840 of the Act;

     "Date of Exercise"             the meaning given to that expression in Rule
                                    5.2

     "Date of Grant"                the date on which the Directors grant an
                                    Option in accordance with the terms of Rule
                                    2;

     "Date of Invitation"           the date on which any notice is given
                                    pursuant to Rule 2.1;

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     "Directors"                    The board of directors for the time being 
                                    of the Company or a duly appointed 
                                    committee thereof;

     "Eligible Employee"            any person (including a full-time director)
                                    who at any Date of Invitation is in the
                                    employment of any Participating Company and
                                    who has been in that employment for at least
                                    one day and who is then chargeable to tax in
                                    respect of such employment under Case I of
                                    Schedule E; or such other person in the
                                    employment of a Participating Company as the
                                    Directors may decide. For the purposes of
                                    this paragraph "full-time" shall mean having
                                    a normal contractual working week of 25
                                    hours or more, excluding meal breaks;

     "Employment"                   employment with the Company and/or any
                                    company under the Control of the Company or
                                    any Associated Company or with any Jointly-
                                    owned Company and "ceasing to be in
                                    Employment" shall be construed as ceasing to
                                    be employed by all such companies;

     "Exchange Rate"                the actual rate of exchange prevailing on
                                    conversion at the Date of Exercise of a
                                    Participant's payment for the exercise of an
                                    Option from Pounds Sterling to US Dollars;

     "Exercise Notice"              the meaning given to that expression in 
                                    Rule 4.3;

     "Group"                        the Company and all its Subsidiaries and
                                    Jointly-owned Companies;

     "Jointly-owned Company"        (a)    a company which is not under the
                                           Control of any single person; and
 
                                    (b)    under the Control of two persons
                                           between them one of such persons 
                                           being the Company; and

                                    (c)    not a participating company in any
                                           other company's group scheme (as
                                           those terms are defined in paragraph
                                           1 of Schedule 9 to the Act )

                                    and any other company which is under the
                                    Control of a company which meets the
                                    conditions in paragraphs (a), (b) and (c)
                                    above and is not itself a participating
                                    company in any other company's group scheme
                                    (as those terms 

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                                    are defined in paragraph 1 of Schedule 9 to
                                    the Act);

     "Minimum Savings Contribution" (Pounds)10 or such other amount specified by
                                    the Directors from time to time, which shall
                                    be no greater than the amount for the time
                                    being specified by paragraph 24(2)(b) of
                                    Schedule 9 to the Act and no lower than the
                                    minimum Savings Contribution permitted by
                                    the relevant Contractual Savings Scheme;
                                     
     "Option"                       the right granted or to be granted on any
                                    particular Date of Grant to acquire Shares
                                    in accordance with the Rules;
                                    
     "Option Certificate"           a certificate evidencing an Option as
                                    referred to in Rule 2.6;
                                    
     "Option Price"                 the price in US Dollars for the acquisition
                                    of a Share comprised in any Option which
                                    shall be determined by the Directors and
                                    shall (subject to the provisions of Rules 6)
                                    be not less than an amount equal to 80 per
                                    cent of the market value of a Share
                                    determined in accordance with sections 272
                                    and 273 of the Taxation of Chargeable Gains
                                    Act 1992 and agreed for the purposes of the
                                    Amgen Limited Sharesave Plan with the Shares
                                    Valuation Division of the Inland Revenue for
                                    the Business Day last preceding the relevant
                                    Date of Invitation;
                             
     "Parent Company"               Amgen Inc. incorporated in the state of
                                    Delaware in the United States of America;
                                     
     "Participant"                  any person (including, where the context
                                    permits, the legal personal representatives
                                    of such a person) who holds an Option;
                             
     "Participating Company"        the Company and any other company within the
                                    Group which the Directors have determined
                                    shall be a Participating Company for the
                                    purposes of the Plan provided that any
                                    Jointly-owned Company which ceases to be a
                                    Jointly-owned Company and which does not
                                    then become a Subsidiary shall cease to be a
                                    Participating Company;
                             
     "Plan"                         this Plan, being the Amgen Limited Sharesave
                                    Plan as adopted by the Directors on [     , 
                                    1998] and as amended from time to time;

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     "Record Date"                 in relation to any particular payment of
                                   dividend or other right attaching to Shares
                                   the date on which the Parent company
                                   determines, in accordance with Delaware law,
                                   the Parent Company By-Laws and the Parent
                                   Company Certificate of Incorporation, a date
                                   to be the record date for holders of the
                                   shares;

     "Redundancy"                  redundancy within the meaning of the
                                   Employment Rights Act 1996;

     "Retirement"                  retirement on reaching age 60 or any other
                                   age at which a Participant is bound to
                                   retire in accordance with the terms of his
                                   contract of employment;

     "Rules"                       these rules together with any amendment
                                   thereto effected in accordance with Rule 7;

     "Savings Contract"            a savings contract entered into under a
                                   Contractual Savings Scheme;

     "Savings Contract Repayment"  in respect of a Savings Contract the amount
                                   in US Dollars at the Exchange Rate of the
                                   repayment of a person's Savings Contributions
                                   plus any bonus or, if the Option is exercised
                                   before the Bonus Date, any interest;
                             
     "Savings Contribution"        the amount payable per month by a Participant
                                   by way of contributions under a Savings
                                   Contract in respect of any Option which
                                   amount shall normally be paid by means of
                                   periodic deductions from the Participant's
                                   remuneration by his employer and shall be an
                                   integral multiple of (Pounds)1 and shall be
                                   not less than the Minimum Savings
                                   Contribution;
                             
     "Share"                       a share in the common stock, par value $.0001
                                   per share, of the Parent Company which
                                   complies with the provisions of paragraphs 10
                                   to 14 of Schedule 9 to the Act;
                             
     "Subsidiary"                  a company which is both under the Control of
                                   the Company and a subsidiary of the Company
                                   within the meaning of Section 736 of the
                                   Companies Act 1985;
                             
     "Withdrawal Notice"           the meaning given to that expression by Rule
                                   4.3.

1.2  Where the context so admits

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     1.2.1   words importing the singular shall include the plural and vice
             versa and words importing the masculine shall include the
             feminine;

     1.2.2   any reference to a statute (or a particular Chapter, Part or
             Section thereof) shall mean and include any statutory
             modification or re-enactment thereof for the time being in
             force and any regulations made thereunder.

2    OFFER AND GRANT OF OPTIONS

2.1  At such time as the Directors shall in their absolute discretion determine
     following the date of approval of the Plan by the Commissioners of Inland
     Revenue, they may give notice to each Eligible Employee on similar terms
     that he is invited to apply for an Option and such notice shall specify:

     2.1.1  the Option Price;

     2.1.2  the period, being not less than fourteen days nor more than twenty-
            one days from the Date of Invitation during which he may apply for
            an Option in accordance with Rule 2.2;

     2.1.3  the Minimum Savings Contribution in respect of the offer;

     2.1.4  the maximum aggregate Savings Contribution permitted under Rule 3.1;
            and

     2.1.5  that the Option will normally be exercisable using the proceeds of a
            Savings Contract on the Bonus Date.

2.2  Subject to Rule 2.7, following any notice to an Eligible Employee by the
     Directors pursuant to Rule 2.1, he may apply for an Option by completing
     and returning an application in such form (not inconsistent with the
     provisions of the Plan) as the Directors may from time to time determine.
     Such form shall specify the Savings Contribution which he wishes to pay and
     authorise the deduction of the Savings Contribution from his remuneration.
     It must be accompanied by a signed form of application concerning his entry
     into a Savings Contract, such form to be in terms acceptable to the body
     administering the Contractual Savings Scheme.

2.3  Within thirty days following the Business Day referred to in the definition
     of Option Price in Rule 1.1 the Directors shall, in respect of each
     Eligible Employee who has made a valid application and who remains in the
     employment of any Participating Company, grant an Option stated to be over
     the number of Shares the aggregate of the Option Prices of which is as
     nearly as possible equal to, but not in excess of, the Savings Contract
     Repayment.  No fractional shares shall be issued upon the exercise of
     rights granted under the Plan.

2.4  Notwithstanding any provision of any other of these Rules whatsoever:

     2.4.1  the Plan shall not form part of any contract of employment between
            the Parent Company, the Company, a Subsidiary, a group or any
            Associated Company and any Participant and it shall not confer on
            any Participant any legal or equitable rights (other than those
            constituted by the Options themselves) whatsoever against the Parent
            Company, the Company, a Subsidiary, a group 

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            or Associated Company or their officers, directors, employees,
            agents or assigns directly or indirectly or give rise to any cause
            of action at law or in equity against the Parent Company, the
            Company, a Subsidiary, a group or any Associated Company or their
            officers, directors, employees, agents or assigns;

     2.4.2  the benefits to the Participants under the Plan shall not form part
            of their wages or remuneration or count as pay or remuneration for
            pension or other purposes;

     2.4.3  the Grant of Options to a Participant is a matter entirely separate
            from any pension right or entitlement he may have and from his terms
            and conditions of employment and participation in the Plan shall in
            no respect whatever affect his pension rights or entitlements or
            terms or conditions of employment and in particular (but without
            limiting the generality of the foregoing) any Participant who ceases
            to be an employee of any Company in the Group or the Parent Company
            or any subsidiary of the Parent Company which is not a member of the
            Group shall not be entitled to any compensation for any loss of any
            right or benefit or prospective right or benefit under the Plan
            which he might otherwise have enjoyed whether such compensation is
            claimed by way of damages for wrongful dismissal or other breach of
            contract or by way of compensation for loss of office or otherwise
            howsoever and notwithstanding that he may have been dismissed
            wrongfully or unfairly (within the meaning of the Employment Rights
            Act 1996);

     2.4.4  No rights granted under the Plan may be exercised to any extent
            unless the Plan (including rights granted thereunder) is covered by
            an effective registration statement pursuant to the Securities Act
            of 1933, as amended (the "Securities Act"). If on a Date of Exercise
            of any Options granted hereunder the Plan is not so registered, no
            rights granted under the Plan shall be exercised on said Date of
            Exercise and the Date of Exercise shall be delayed until the Plan is
            subject to such an effective registration statement, except that the
            Date of Exercise shall not be delayed more than two (2) months and
            the Date of Exercise shall in no event be later than the last date
            on which the Option can be exercised under Rule 4. If on the Date of
            Exercise of any Option granted hereunder, as delayed to the maximum
            extent permissible, the Plan is not registered the Option shall
            lapse.

2.5  An Option shall be personal to the Participant and shall not be assignable
     and any purported assignment, transfer, charge, disposal or dealing with
     the rights or interests of the Participant under the Plan shall render the
     Option void.  However, on the death of a Participant, an Option shall be
     capable of being exercised by his legal personal representatives in
     accordance with the provisions of Rule 4.

2.6  As soon as is practicable upon the grant of an Option to a person pursuant
     to Rule 2.3 the Directors shall issue to the said person an Option
     Certificate evidencing such Option.  The Option Certificate shall specify
     the estimated number of Shares comprised in the Option based on current
     exchange rates at the Date of Grant, the Date of Grant and the Option Price
     in respect of each such Share and shall be otherwise in such form (not
     inconsistent with the provisions of the Plan) as the Directors may from
     time to time determine.  If any such certificate shall be worn out,

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     defaced, destroyed or lost, it may be renewed on such evidence being
     provided and on such terms as the Directors may reasonably require.

2.7  No Option shall be granted to any person (i) unless he is an employee of a
     Participating Company on the Date of Grant or (ii) if such person is
     ineligible to participate in the Plan by virtue of the provisions of
     paragraph 8 of Schedule 9 to the Act.

3    Individual participation limits

3.1  The aggregate of the Savings Contributions being made at any time by a
     Participant under the Plan (and any contributions then being made under
     certified contractual savings schemes linked to any other savings-related
     scheme or schemes approved under Schedule 9 to the Act) shall not exceed
     (Pounds)250 per month (or such other amount as the Directors may determine
     as may be permitted pursuant to paragraph 24 of Schedule 9 to the Act).

3.2  Applications made under Rule 2.2 shall be scaled down, if necessary, to
     ensure that the number of shares which may be issued on the exercise in
     full of all Options granted on any Date of Grant shall not exceed 100,000
     Shares on the assumption that the prospective savings contract repayment
     for each Eligible Employee to whom an Option is to be granted on such Date
     of Grant is converted into U.S. dollars at the exchange rate prevailing on
     that Date of Grant.  Any scaling down shall be done by the Directors who
     shall reduce the excess over (Pounds)10 of the monthly savings
     contributions chosen by each applicant on a pro rata basis and to the
     extent necessary.

     Each application under Rule 2.2 shall then be deemed to have been modified
     or withdrawn in accordance with the said scaling down and the Directors
     shall amend each application for a Savings Contract to reflect any
     resulting reduction in monthly savings contributions.

4    EXERCISE AND LAPSE OF OPTIONS

4.1  An Option shall be capable of being exercised in whole or in part following
     the earliest of :-

     4.1.1  the Bonus Date if the Participant is an employee or director of a
            Participating Company;

     4.1.2  the Bonus Date if the Participant is an employee or director of a
            company which is not a Participating Company but which is an
            Associated Company or a company of which the Company has Control;

     4.1.3  the death of the Participant;

     4.1.4  the Participant ceasing to be in Employment by reason of his
            Retirement, injury, disability or Redundancy;

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     4.1.5  the Participant ceasing to be in Employment more than three years
            from its Date of Grant by reason of retirement on receipt of a
            pension under any pension scheme of which he is a member in respect
            of his Employment;

     4.1.6  the Participant ceasing to be in Employment by reason that his
            Employment is in a company of which the Company ceases to have
            Control, or it relates to a business or part of a business which is
            transferred to a person who is neither an Associated Company of the
            Company nor a company of which the Company has Control;

     4.1.7  the Participant reaching age 60 and continuing to be in Employment
            in which case the right to exercise an Option under this sub-
            paragraph is available for a period of six months following
            attainment of such age provided that if he does not exercise such
            Option within the said period of six months he will nevertheless be
            able to exercise the Option on the next earliest event covered by
            this Rule 4.1;

     provided that

     (I)  no Option shall be capable of being exercised other than at a time
          when the Participant is in Employment except in the circumstances
          described in Rules 4.1.3, 4.1.4, 4.1.5 and 4.1.6; and

     (II) no Option shall be capable of being exercised at a time when paragraph
          8 of Schedule 9 to the Act would disqualify the Participant from being
          granted an Option, nor by the personal representatives of a
          Participant who was so precluded at the date of his death.

4.2  In no event shall an Option be capable of being exercised in respect of a
     number of Shares the aggregate Option Prices of which exceed the repayment
     made (including any bonus or interest but excluding the repayment of any
     contributions the due date for payment of which falls more than one month
     after the date on which repayment is made) to the Participant under the
     related Savings Contract.

4.3  An Option shall lapse to the extent that it has not been exercised by the
     earliest of:-

     4.3.1  the expiry of six months from the Bonus Date except where the death
            of the Participant occurs before the expiry of such period;

     4.3.2  if the Participant dies before the Bonus Date, the expiry of twelve
            months from the date of death of the Participant;

     4.3.3  the expiry of twelve months from the Bonus Date where the death of
            the Participant occurs within six months after the Bonus Date;

     4.3.4  the expiry of six months from the date on which the Participant
            ceased to be in Employment in the circumstances described in Rules
            4.1.4, 4.1.5 or 4.1.6, except where the death of the Participant
            occurs before the expiry of such period;

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     4.3.5  the date on which the Participant ceases to be in Employment for any
            reason other than death or any of the circumstances referred to in
            Rule 4.1.4, 4.1.5 or 4.1.6;

     4.3.6  the Participant's right to continue making the related Savings
            Contributions lapsing in respect of an Option in accordance with the
            provisions of the Contractual Savings Scheme before the Participant
            has made all the Savings Contributions required by the Contractual
            Savings Scheme unless such Option has already become exercisable
            under the provisions of this Rule;

     4.3.7  the receipt by the body administering the Contractual Savings Scheme
            of a Withdrawal Notice in respect of the Savings Contract relative
            to such Option provided that such Option is not then capable of
            being exercised; and

     4.3.8  the date on which an Option lapses pursuant to Rule 6.

     The Participant may direct at any time by notice (referred to as a
     "Withdrawal Notice") given in writing in a form acceptable to the body
     administering the Contractual Savings Scheme that he wishes such repayment
     as is then due to him to be made under the Savings Contract relative to any
     Option and in addition, if such notice is given in respect of the Savings
     Contract relative to any Option which the Participant then wishes to
     exercise in whole or in part, notice to that effect shall be given to the
     Company in such form as the Directors may prescribe (referred to as an
     "Exercise Notice").

5    MANNER OF EXERCISE OF OPTIONS

5.1  In order to exercise an Option the Participant shall give to the Directors
     (or their nominated agent) an Exercise Notice stating that the Option is to
     be exercised on the Date of Exercise in respect of that number of Shares
     the aggregate Option Prices of which are as nearly as possible equal to,
     but not in excess of, the US Dollar equivalent at the Exchange Rate of the
     Sterling amount specified in the Exercise Notice which must be equal to or
     less than the repayment due under the related Savings Contract that he
     wishes to be applied in respect of the exercise of the Option.  Such
     Exercise Notice shall be accompanied by payment (or an authority to obtain
     such payment from the body administering the Savings Contract) in full of
     the Sterling amount specified.  It shall be the responsibility of the
     Participant to obtain any exchange control consents or other authorities
     required to enable him to exercise his Option and receive the Shares to be
     transferred or issued in respect thereof.

5.2  The Date of Exercise shall be the last day of the calendar month following
     the month in which the Directors receive the Exercise Notice, Option
     Certificate and Sterling proceeds of repayment under the Savings Contract
     specified in the Exercise Notice (provided that if such day is not a
     working day in the United Kingdom the next working day) or, if  earlier,
     the last day of any period referred to in Rule 4.3

5.3  Subject to such consents or other required action of any competent
     authority under regulations or enactments for the time being in force as
     may be necessary, within thirty days after the Date of Exercise the Parent
     Company shall arrange for the transfer or 

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     issue of the appropriate number of shares and the transferee or allottee
     shall be entered in the books of the Parent Company in respect of these
     Shares. The said Shares shall rank in full for all dividends and other
     rights to which a right arises by reference to a Record Date falling on or
     after the date on which the transferee or allottee is entered in the books
     of the Parent Company and shall in all other respects rank pari passu with
     the other Shares of the same class and shall be acquired subject to the
     Parent Company's By-laws.

5.4  Where an Option is exercised in part, it shall lapse to the extent of the
     unexercised balance.

5.5  The Parent Company shall ensure that sufficient Shares are always available
     to satisfy in full all outstanding Options.

6    Adjustments upon changes in shares

6.1  If any change is made in the shares, or subject to any rights granted under
     the Plan (through merger, consolidation, reorganisation, recapitalisation,
     stock dividend, dividend in property other than cash, stock split,
     liquidating dividend, combination of shares, exchange of shares, change in
     corporate structure or other transaction not involving the receipt of
     consideration by the Parent Company), the Plan and outstanding rights will
     be appropriately adjusted in the class(es) and maximum number of Shares
     subject to the Plan and the class(es) and number of Shares and price per
     Share of stock subject to outstanding rights.  Such adjustments shall be
     made by the Directors, the determination of which shall be final, binding
     and conclusive, subject to the Inland Revenue's consent.  (The conversion
     of any convertible securities of the Parent Company shall not be treated as
     a "transaction not involving the receipt of consideration by the Parent
     Company").

6.2  If any person obtains Control of the Parent Company as a result of making

     6.2.1  a general offer to acquire the whole of the issued ordinary share
            capital of the Parent Company which is made on a condition such that
            if it is satisfied the person making the offer will have Control of
            the Parent Company; or

     6.2.2  a general offer to acquire all (or substantially all) the shares in
            the Parent Company which are of the same class as the Shares over
            which Options have been granted

     then all outstanding Options shall lapse on the date on which such Control
     is obtained.

6.3  For the purposes of this Rule 6 a person shall be deemed to have obtained
     Control of a Company if he and others acting in concert with him have
     together obtained Control of it.

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7    Amendment and administration

7.1  The Plan may be amended by resolution of the Directors provided that no
     amendment shall:

     7.1.1  operate to disadvantage any rights already acquired by a Participant
            under the Plan without his consent;

     7.1.2  have effect until it has been approved by the Commissioners of
            Inland Revenue.

7.2  Notwithstanding Rule 7.1.1 but subject to Rule 7.1.2, the Directors may by
     resolution amend the Plan in any way but only to the extent necessary or
     desirable to secure or maintain the approval of the Plan by the
     Commissioners of Inland Revenue under Schedule 9 to the Act.

7.3  Subject as herein otherwise expressly provided the Directors' decision on
     any matter concerning the Plan shall be final and binding.

7.4  The costs of the operation of the Plan shall be borne by the Company.

7.5  The Plan and Options granted under it shall be governed by and construed in
     accordance with English Law (except where otherwise stated) and all
     disputes shall be referred for resolution to the courts of England,
     provided that issues pertaining to or concerning the Shares and/or the
     Parent Company shall be governed by and construed in accordance with
     Delaware Law.

7.6  In any matter in which they are required to act hereunder the Auditors
     shall be deemed to be acting as experts and not as arbitrators and the
     Arbitration Acts 1950-1979 shall not apply hereto.

7.7  All notices under the Plan shall be in writing and, if to the Company,
     shall be either delivered in person to the Company Secretary or sent to the
     Company's registered office for the time being (or to such other address as
     the Directors may from time to time specify) and, if to a Participant,
     shall be delivered personally to him at his place of work or sent by first-
     class post to the Participant at the address which he shall give in writing
     to the Company for this purpose, or, failing any such address, his last
     known place of abode.   All notices to the Company, however sent, shall be
     deemed to be served only upon actual receipt thereof by the Company
     Secretary or (as the case may be) at the appropriate address as determined
     above.  Notices to the Participant shall, if delivered personally to him at
     his place of work, be deemed to be served upon such delivery and, if sent
     by first-class post to the appropriate address as determined above, shall
     be deemed to be served forty-eight hours after the posting to such address
     of a properly addressed and prepaid envelope containing such notice.

8    TERMINATION

The Directors may at any time resolve that no further offers of participation
shall be made under the Plan but in such event the subsisting rights of
Participants will not thereby be affected.

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