EXHIBIT 4-3



                               DEED OF GUARANTEE

THIS DEED OF GUARANTEE is made on 16th June, 2000 by CIBA SPECIALTY CHEMICALS
HOLDING INC., (the "Guarantor") in favour of the Relevant Account Holders (as
defined in the Deed of Covenant referred to below) and the holders for the time
being of the Notes (as defined below) and the interest coupons (if any)
appertaining to the Notes ("Coupons"), the Coupons being attached on issue to
Definitive Note(s) (as defined below). Each Relevant Account Holder, each holder
of a Note and each holder of a Coupon is a "Holder".

WHEREAS:

(A)  CIBA SPECIALTY CHEMICALS CORPORATION, CIBA SPECIALTY CHEMICALS PLC, CIBA
     SPEZIALITATENCHEMIE HOLDING DEUTSCHLAND GMBH (the "Issuers " and each an
     "Issuer") and the Guarantor have entered into an amended and restated
     Program Agreement (the "Program Agreement", which expression includes the
     same as it may be amended or supplemented from time to time) dated 16th
     June, 2000 with the Dealers named therein, which amends and restates the
     amended and restated program agreement entered into by, inter alia, Ciba
     Specialty Chemicals Corporation, Ciba Specialty Chemicals PLC and Ciba
     Spezialitatenchemie Holding Deutschland GmbH dated 9th July, 1999 (the
     "Principal Program Agreement"), under which each Issuer proposes from time
     to time to issue Euro Medium Term Notes (the "Notes", such expression to
     include each Definitive Note issued by an Issuer and each Global Note
     issued by an Issuer (where "Definitive Note" and "Global Note" have the
     meanings ascribed thereto in the Agency Agreement defined below) and to
     include any receipts issued in respect of Notes repayable in instalments);

(B)  each Issuer has executed a Deed of Covenant of even date (the "Deed of
     Covenant") relating to Global Notes issued by that Issuer pursuant to the
     Program Agreement;

(C)  the Issuers and the Guarantor have entered into an amended and restated
     agency agreement (the "Agency Agreement", which expression includes the
     same as it may be amended or supplemented from time to time) dated 16th
     June, 2000 with the Paying Agents named therein; and

(D)  this Deed of Guarantee amends and restates the amended and restated Deed of
     Guarantee made by the Guarantor dated 9th July, 1999, and does not affect
     any Notes issued pursuant to the Original Program Agreement prior to the
     date hereof.

NOW THIS DEED WITNESSES as follows:

1.   Guarantee: The Guarantor irrevocably and unconditionally undertakes to
     secure by way of deed poll to each Holder the due and punctual payment as
     stipulated in an Issuer's Note or Coupon or under its Deed of Covenant, as
     the case may be. The Guarantor therefore undertakes to pay on first demand
     of such a Holder, irrespective of the validity and the legal


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     effects of the above mentioned relationship in respect of a Note or Coupon
     or Deed of Covenant and waiving all rights of objection and defence arising
     therefrom any amount not paid by the relevant Issuer (including any premium
     or any other amounts of whatever nature or additional amounts) upon receipt
     of the written request for payment by such Holder and the confirmation in
     writing by the Agent that the relevant Issuer has not made such payments on
     the dates specified and in the amount called under the Guarantee. The
     Guarantor hereby expressly undertakes and secures that payments under this
     Guarantee will not be less than as stipulated in an Issuer's Note or
     Coupon. In implementation of this undertaking and in case Swiss withholding
     taxes are imposed in respect of payments made under this Guarantee, the
     Guarantor undertakes, as a separate and independent obligation, to pay an
     increased amount on the relevant Note or Coupon so that the payment
     received by the Noteholder or Couponholder shall equal the amount actually
     stipulated in such Note or Coupon (assuming no such withholding applies).

2.   Guarantor's Obligations Continuing: The Guarantor's obligations under this
     Guarantee are and will remain in full force and effect by way of continuing
     security until no sum remains payable under any Note, any Coupon or the
     Deed of Covenant. Furthermore, these obligations of the Guarantor are
     additional to, and not instead of, any security or other guarantee or
     indemnity at any time existing in favour of a Holder, whether from the
     Guarantor or otherwise. The Guarantor irrevocably waives all notices and
     demands whatsoever, except as provided herein.

3.   Repayment to the Issuer: If any payment received by a Holder is, on the
     subsequent liquidation or insolvency of the relevant Issuer, avoided under
     any laws relating to liquidation or insolvency, such payment will not be
     considered as having discharged or diminished the liability of the
     Guarantor and this Guarantee will continue to apply as if such payment had
     at all times remained owing by the relevant Issuer.

4.   Status of Guarantee: The payment obligations of the Guarantor under this
     Guarantee constitute direct, unconditional and (subject to Clause 5 below)
     unsecured obligations of the Guarantor and (subject as aforesaid) rank and
     will rank pari passu with all other outstanding unsecured and
     unsubordinated indebtedness and monetary obligations of the Guarantor,
     present or future, including those in respect of deposits (other than
     obligations preferred by law).

5.   Negative Pledge of the Guarantor: So long as any of the Notes remains
     outstanding, but not later than the time when payment for the full amount
     of principal and interest in respect of all outstanding Notes has been duly
     provided for, the Guarantor will procure that no Indebtedness of the
     Guarantor which is represented by bonds, notes or other securities which in
     any such case are listed or capable of being listed on any recognised stock
     exchange will be secured upon any of the present or future assets or
     revenues of the Guarantor unless all amounts payable under this Guarantee
     are secured equally and rateably with such other security or such other
     security or guarantee is granted to the Notes and Coupons as shall have
     been approved by an Extraordinary Resolution of the Noteholders.


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     Any reference to an obligation being guaranteed shall include a reference
     to an indemnity being given in respect of payment thereof.

     As used herein "Indebtedness" means all indebtedness for money borrowed
     that is created, assumed, incurred or guaranteed in any manner by the
     Guarantor or for which the Guarantor is otherwise responsible or liable.

6.   Tax Gross-up: All payments in respect of the Notes by the Guarantor shall
     be made without withholding or deduction for, or on account of, any present
     or future taxes, duties, assessments or governmental charges of whatever
     nature ("Taxes") imposed or levied by or on behalf of Switzerland, or any
     political sub-division of, or any authority in, or of, Switzerland having
     power to tax, unless the withholding or deduction of the Taxes is required
     by law. In that event, the Guarantor will pay such additional amounts as
     may be necessary in order that the net amounts received by the Noteholders
     and Couponholders after the withholding or deduction shall equal the
     respective amounts which would have been receivable in respect of the Notes
     or, as the case may be, Coupons in the absence of the withholding or
     deduction; except that no additional amount shall be payable in relation to
     any payment in respect of any Note or Coupon:

     (i)  by or on behalf of a person liable to such tax, duty or charge in
          respect of such Note, Receipt or Coupon by reason of his having some
          connection with Switzerland other than the mere holding or ownership
          of such Note, Receipt or Coupon; and/or

    (ii)  presented for payment to the relevant Issuer more than 30 days after
          the Relevant Date (as defined in Condition 7(f) of the Terms and
          Conditions of the relevant Notes) except to the extent that a holder
          would have been entitled to additional amounts on presenting the same
          for payment on the last day of the period of 30 days; and/or

   (iii)  to, or to a third party on behalf of, a holder who would be able to
          avoid such withholding or deduction by making a declaration of
          non-residence or similar claim for exemption but fails to do so.

7.   Power to execute: The Guarantor hereby warrants, represents and covenants
     with each Holder that it has all corporate power, and has taken all
     necessary corporate or other steps, to enable it to execute, deliver and
     perform this Guarantee, and that this Guarantee constitutes a legal, valid
     and binding obligation of the Guarantor, enforceable in accordance with its
     terms subject to applicable bankruptcy, reorganisation, insolvency,
     fraudulent transfer, moratorium and other similar laws affecting creditor's
     rights generally from time to time in effect, and to general principles of
     equity, regardless of whether considered in a proceeding in law or at
     equity.

8.   Deposit of Guarantee: This Guarantee shall take effect as a Deed Poll for
     the benefit of the Holders from time to time and for the time being. This
     Guarantee shall be deposited with


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     and held by The Chase Manhattan Bank for the benefit of the Holders until
     all the obligations of the Guarantor hereunder have been discharged in
     full.

9.   Production of Guarantee: The Guarantor hereby acknowledges the right of
     every Holder to the production of, and the right of every Holder to obtain
     (upon payment of a reasonable charge) a copy of, this Guarantee, and
     further acknowledges and covenants that the obligations binding upon it
     contained herein are owed to, and shall be for the account of, each and
     every Holder, and that each Holder shall be entitled severally to enforce
     the said obligations against the Guarantor.

10.  Subrogation: Until all amounts which may be payable under the Notes, the
     Coupons and/or the Deed of Covenant have been irrevocably paid in full, the
     Guarantor shall not exercise any rights of subrogation in respect of any
     rights of any Holder or claim in competition with the Holders against the
     relevant Issuer.

11.  Governing Law and Jurisdiction: This Guarantee is governed by and shall be
     construed in accordance with English law. The Guarantor irrevocably agrees
     for the benefit of each Holder that the courts of England are to have
     jurisdiction to settle any disputes which may arise out of or in connection
     with this Guarantee and that accordingly any suit, action or proceedings
     arising out of or in connection with this Guarantee (together referred to
     as "Proceedings") may be brought in the courts of England.

     The Guarantor irrevocably waives any objection which it may have now or
     hereafter to the laying of the venue of the Proceedings in the courts of
     England and irrevocably agrees that a final judgment in any Proceedings
     brought in the courts of England shall be conclusive and binding upon the
     Guarantor and may be enforced in the courts of any other jurisdiction.
     Nothing contained in this Clause shall limit any right to take Proceedings
     against the Guarantor in any other court of competent jurisdiction, nor
     shall the taking of Proceedings in none or more jurisdictions preclude the
     taking of Proceedings in any other jurisdiction, whether concurrently or
     not.

     The Guarantor hereby appoints Ciba Specialty Chemicals PLC as its agent for
     service of process in England in respect of any Proceedings and undertakes
     that in the event of it ceasing so to act it will appoint another person as
     its agent for that purpose.

IN WITNESS whereof this Guarantee has been manually executed as a deed poll on
behalf of the Guarantor.

Executed as a deed          )
by CIBA SPECIALTY CHEMICALS )
HOLDING INC.                )
acting by its attorneys     )
and                         )
                            )


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in the presence of:         )



Witness's
Signature: .............................

Name:      .............................

Address:   .............................

           .............................



Dated 16th June, 2000


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                             Dated 16th June, 2000






                     CIBA SPECIALTY CHEMICALS HOLDING INC.











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

                               DEED OF GUARANTEE
                             (Amended and Restated)

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












                                 ALLEN & OVERY
                                     London