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                                                                     Exhibit 4.3

                               AMENDMENT NO. 1 TO
                                RIGHTS AGREEMENT

         THIS AMENDMENT NO. 1 TO RIGHTS AGREEMENT (this "Amendment") is made and
entered into as of March 6, 2000 by and between K-Tron International, Inc., a
New Jersey corporation (the "Company") and American Stock Transfer & Trust
Company (the "Rights Agent"). This Amendment amends and otherwise modifies the
Rights Agreement (the "Agreement") dated as of October 3, 1991 by and between
the Company and First Interstate Bank of Arizona, N.A., the predecessor Rights
Agent. Terms used herein that are not defined herein shall have the meanings
ascribed thereto in the Agreement.

         WHEREAS, in accordance with Section 26(a) of the Agreement, the Company
and the Rights Agent wish to change certain provisions of the Agreement in a
manner that the Company deems necessary or desirable and that does not adversely
affect the interests of the holders of Rights Certificates.

         NOW, THEREFORE, the parties hereto, intending to be legally bound,
hereby agree as follows:

         1. Section 1(g) shall be amended and restated in its entirety to read
as follows:

                    (g) Intentionally left blank.

         2. Section 11(a)(ii)(B) of the Agreement shall be amended and restated
in its entirety to read as follows:

                            (B) any Person (other than the Company, any
            Subsidiary of the Company, any employee benefit plan of the Company
            or of any Subsidiary of the Company, or any Person or entity
            organized, appointed or established by the Company for or pursuant
            to the terms of any such plan), alone or together with its
            Affiliates and Associates, shall, at any time after the Rights
            Dividend Declaration Date, become the Beneficial Owner of 20% or
            more of the Common Shares then outstanding, unless the event causing
            the 20% threshold to be crossed is a Section 13 Event, or is an
            acquisition of Common Shares pursuant to a tender offer or an
            exchange offer for all outstanding Common Shares at a price and on
            terms that provide fair value to all shareholders, as determined by
            at least a majority of the Board of Directors of the Company, after
            taking into consideration all factors that such members of the
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            Board of Directors deem relevant, including, without limitation, the
            long-term prospects and value of the Company and the prices and
            terms that such members of the Board of Directors believe, in good
            faith, could reasonably be achieved if the Company or its assets
            were sold on an orderly basis designed to realize maximum value, or

         3. Section 11(a)(iii) of the Agreement shall be amended and restated in
its entirety to read as follows:

                            (iii) In the event that the number of Common Shares
            that are authorized by the Company's Restated Certificate of
            Incorporation but not outstanding or reserved for issuance for
            purposes other than upon exercise of the Rights are not sufficient
            to permit the exercise in full of the Rights in accordance with the
            foregoing subparagraph (ii) of this Section 11(a), the Company
            shall: (A) determine the excess of the value of the Adjustment
            Shares issuable upon the exercise of a Right (the "Current Value")
            over the Purchase Price (such excess, the "Spread"), and (B) with
            respect to each Right, make adequate provision to substitute for the
            Adjustment Shares, upon payment of the applicable Purchase Price,
            (1) cash, (2) a reduction in the Purchase Price, (3) Common Shares
            of the same or a different class or other equity securities of the
            Company (including, without limitation, preferred shares or units of
            preferred shares that a majority of the Board of Directors of the
            Company has deemed (based, among other things, on the dividend and
            liquidation rights of such preferred shares) to have substantially
            the same economic value as Common Shares (such preferred shares,
            hereinafter referred to as "common share equivalents")), (4) debt
            securities of the Company, (5) other assets, or (6) any combination
            of the foregoing, having an aggregate value equal to the Current
            Value, where such aggregate value has been determined by a majority
            of the Board of Directors of the Company after considering the
            advice of a nationally recognized investment banking firm selected
            by the Board of Directors of the Company; provided, however, if the
            Company shall not have made adequate provision to deliver value
            pursuant to clause (B) above within thirty (30) days following the
            later of (x) the first occurrence of a Section 11(a)(ii) Event and
            (y) the date on which the Company's right of redemption pursuant to
            Section 23(a) expires (the later of (x) and (y) being referred to
            herein as the "Section 11(a)(ii) Trigger Date"), then the Company
            shall be obligated to deliver, upon the surrender for exercise of a
            Right and


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            without requiring payment of the Purchase Price, Common Shares (to
            the extent available) and then, if necessary, cash, which shares
            and/or cash have an aggregate value equal to the Spread. If the
            Board of Directors of the Company shall determine in good faith that
            it is likely that sufficient additional Common Shares could be
            authorized for issuance upon exercise in full of the Rights, the
            thirty (30) day period set forth above may be extended to the extent
            necessary, but not more than ninety (90) days after the Section
            11(a)(ii) Trigger Date, in order that the Company may seek
            shareholder approval for the authorization of such additional shares
            (such period, as it may be extended, the "Substitution Period"). To
            the extent that the Company determines that some action need be
            taken pursuant to the first and/or second sentences of this Section
            11(a)(iii), the Company shall provide, subject to Section 7(e)
            hereof, that such action shall apply uniformly to all outstanding
            Rights, and may suspend the exercisability of the Rights until the
            expiration of the Substitution Period in order to seek any
            authorization of additional shares and/or to decide the appropriate
            form of distribution to be made pursuant to such first sentence and
            to determine the value thereof. The Company shall make a public
            announcement when the exercisability of the Rights has been
            temporarily suspended, and again when such suspension is no longer
            in effect. For purposes of this Section 11(a)(iii), the value of the
            Common Shares shall be the current market price (as determined
            pursuant to Section 11(d) hereof) per Common Share on the Section
            11(a)(ii) Trigger Date and the value of any "common share
            equivalent" shall be deemed to have the same value as the Common
            Shares on such date.

         4. Section 11(q) of the Agreement shall be amended and restated in its
entirety to read as follows:

                            (q) In the event that the Rights become exercisable
            following a Section 11(a)(ii) Event, the Company, by action of a
            majority of the Board of Directors of the Company, may permit the
            Rights, subject to Section 7(e) hereof, to be exercised for 50% of
            the Common Shares (or cash or other securities or assets to be
            substituted for the Adjustment Shares pursuant to subsection
            (a)(iii)) that would otherwise be purchasable under subsection (a),
            in consideration of the surrender to the Company of the Rights so
            exercised and without other payment of the Purchase Price. Rights
            exercised under this subsection (q) shall be deemed to have been
            exercised in full and shall be canceled.


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         5. Section 13(e) of the Agreement shall be amended and restated in its
entirety to read as follows:

                            (e) In the event that the Rights become exercisable
            under subsection (a) (except as provided in subsection (d)), the
            Company, by action of a majority of the Board of Directors of the
            Company, may agree with the Principal Party that the Principal Party
            shall permit the Rights to be exercised for 50% of the Common Shares
            of the Principal Party that would otherwise be purchasable under
            subsection (a), in consideration of the surrender to the Principal
            Party, as the successor to the Company under subsection (a)(ii), of
            the Rights so exercised and without other payment of the Purchase
            Price. Rights exercised under this subsection (e) shall be deemed to
            have been exercised in full and shall be canceled.

         6.       Section 21 of the Agreement shall be amended and restated in
its entirety to read as follows:

                            SECTION 21. Change of Rights Agent. The Rights Agent
            or any successor Rights Agent may resign and be discharged from its
            duties under this Agreement upon thirty (30) days' prior written
            notice mailed to the Company and to each transfer agent of the
            Common Shares and Preferred Shares by registered or certified mail,
            and to the holders of the Rights Certificates by first-class mail.
            The Company may remove the Rights Agent or any successor Rights
            Agent upon thirty (30) days' prior written notice mailed to the
            Rights Agent or successor Rights Agent, as the case may be, and to
            each transfer agent of the Common Shares and Preferred Shares, by
            registered or certified mail, and to the holders of Rights
            Certificates by first-class mail. If the Rights Agent shall resign
            or be removed or shall otherwise become incapable of acting, the
            Company shall appoint a successor to the Rights Agent. If the
            Company shall fail to make such appointment within a period of
            thirty (30) days after giving notice of such removal or after it has
            been notified in writing of such resignation or incapacity by the
            resigning or incapacitated Rights Agent or by the holder of a Rights
            Certificate (who shall, with such notice, submit his Rights
            Certificate for inspection by the Company), then any registered
            holder of any Rights Certificate may apply to any court of competent
            jurisdiction for the appointment of a new Rights Agent. Any
            successor Rights Agent, whether appointed by the


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            Company or by such a court, shall be (a) a corporation organized,
            doing business and in good standing under the laws of the United
            States or of any state, having a principal office in the State of
            New York or the State of New Jersey, that is authorized by law to
            exercise corporate trust and stock transfer powers and is subject to
            supervision or examination by federal or state authority and that
            has at the time of its appointment as Rights Agent a combined
            capital and surplus adequate in the judgment of a majority of the
            Board of Directors of the Company to assure the performance of its
            duties hereunder and the protection of the interests of the Company
            and the holders of Rights or beneficial interests therein, or (b) an
            Affiliate of a corporation described in clause (a) of this sentence.
            After appointment, the successor Rights Agent shall be vested with
            the same powers, rights, duties and responsibilities as if it had
            been originally named as Rights Agent without further act or deed;
            but the predecessor Rights Agent shall deliver and transfer to the
            successor Rights Agent any property at the time held by it
            hereunder, and execute and deliver any further assurance,
            conveyance, act or deed necessary for that purpose. Not later than
            the effective date of any such appointment, the Company shall file
            notice thereof in writing with the predecessor Rights Agent and each
            transfer agent of the Common Shares and Preferred Shares and mail a
            notice thereof in writing to the registered holders of the Rights
            Certificates or, prior to the Distribution Date, to the registered
            holders of the Common Shares. Failure to give any notice provided
            for in this Section 21, however, or any defect therein, shall not
            affect the legality or validity of the resignation or removal of the
            Rights Agent or the appointment of the successor Rights Agent, as
            the case may be.

         7. Section 23(a) of the Agreement shall be amended and restated in its
entirety to read as follows:

                            (a) The Board of Directors of the Company may, at
            its option, at any time prior to the earlier of (i) the close of
            business on the tenth day following a Stock Acquisition Date (or, if
            the Stock Acquisition Date shall have occurred prior to the Record
            Date, the close of business on the tenth day following the Record
            Date), or (ii) the Final Expiration Date, redeem all but not less
            than all the then outstanding Rights at a redemption price of $0.01
            per Right, as such amount may be appropriately adjusted to reflect
            any stock split, stock dividend or similar transaction occurring
            after the date hereof (such redemption price being hereinafter
            referred to as the


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            "Redemption Price") and the Company may, at its option, pay the
            Redemption Price either in Common Shares (based on the "current
            market price", as defined in Section 11(d)(i) hereof, of the Common
            Shares at the time of redemption) or cash; provided, however, if,
            following the occurrence of a Stock Acquisition Date and following
            the expiration of the right of redemption hereunder but prior to any
            Triggering Event, (i) an Acquiring Person shall have transferred or
            otherwise disposed of a number of Common Shares in one transaction
            or a series of transactions, not directly or indirectly involving
            the Company or any of its Subsidiaries, which did not result in the
            occurrence of a Triggering Event or the Company shall have issued
            additional equity securities, in either instance such that such
            Person is thereafter a Beneficial Owner of 10% or less of the
            outstanding Common Shares, and (ii) there is no other Acquiring
            Person immediately following the occurrence of the event described
            in clause (i), then the right of redemption shall be reinstated and
            thereafter be subject to the provisions of this Section 23.
            Notwithstanding anything contained in this Agreement to the
            contrary, the Rights shall not be exercisable after the first
            occurrence of a Section 11(a)(ii) Event until such time as the
            Company's right of redemption hereunder has expired.

         8. Section 26(a) of the Agreement shall be amended and restated in its
entirety to read as follows:

                            (a) Prior to the Distribution Date and subject to
            the penultimate sentence of this Section 26, the Company and the
            Rights Agent shall, if the Company so directs, supplement or amend
            any provision of this Agreement without the approval of any holders
            of certificates representing Common Shares. From and after the
            Distribution Date and subject to the penultimate sentence of this
            Section 26, the Company and the Rights Agent shall, if the Company
            so directs, supplement or amend this Agreement without the approval
            of any holders of Rights Certificates in order (i) to cure any
            ambiguity, (ii) to correct or supplement any provision contained
            herein which may be defective or inconsistent with any other
            provisions herein, (iii) to shorten or lengthen any time period
            hereunder, or (iv) to change or supplement the provisions hereunder
            in any manner that the Company may deem necessary or desirable and
            that shall not adversely affect the interests of the holders of
            Rights Certificates; provided, this Agreement may not be
            supplemented or amended to lengthen, pursuant to clause (iii) of
            this sentence, (A) a time period


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            relating to when the Rights may be redeemed at such time as the
            Rights are not then redeemable, or (B) any other time period unless
            such lengthening is for the purpose of protecting, enhancing or
            clarifying the rights of and/or the benefits to, the holders of
            Rights. Upon the delivery of a certificate from an appropriate
            officer of the Company that states that the proposed supplement or
            amendment is in compliance with the terms of this Section 26, the
            Rights Agent shall execute such supplement or amendment and shall be
            fully protected hereunder by doing so. Nothing herein shall require
            the Rights Agent to execute any supplement or amendment adversely
            affecting its rights and protections hereunder. Notwithstanding
            anything contained in this Agreement to the contrary, no supplement
            or amendment shall be made that changes the Redemption Price, the
            Final Expiration Date, the Purchase Price or the number of Preferred
            Share Fractions for which a Right is exercisable. Prior to the
            Distribution Date, the interests of the beneficial owners of Rights
            shall be deemed coincident with the interests of the holders of
            Common Shares.

         9.       Section 28 of the Agreement shall be amended and restated in
its entirety to read as follows:

                            SECTION 28. Determinations and Actions by the Board
            of Directors, etc. For all purposes of this Agreement, any
            calculation of the number of Common Shares outstanding at any
            particular time, including for purposes of determining the
            particular percentage of such outstanding Common Shares of which any
            Person is the Beneficial Owner, shall be made in accordance with the
            last sentence of Rule 13d-3(d)(1)(i) of the General Rules and
            Regulations under the Exchange Act. The Board of Directors of the
            Company shall have the exclusive power and authority to administer
            this Agreement and to exercise all rights and powers specifically
            granted to the Board or to the Company, or as may be necessary or
            advisable in the administration of this Agreement, including,
            without limitation, the right and power to (i) interpret the
            provisions of this Agreement, and (ii) make all determinations
            deemed necessary or advisable for the administration of this
            Agreement (including a determination to redeem or not redeem the
            Rights or to amend or supplement the Agreement). All such actions,
            calculations, interpretations and determinations (including, for
            purposes of clause (y) below, all omissions with respect to the
            foregoing) that are done or made by the Board in good faith, shall
            (x) be final, conclusive and binding on the Company, the Rights


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            Agent, the holders of the Rights and all other parties, and (y) not
            subject the Board to any liability to the holders of the Rights.

         10. This Amendment shall be effective as of March 6, 2000 and shall be
governed by and interpreted under the laws of the State of New Jersey, without
giving effect to any conflict of laws provisions.

         11. As amended and modified hereby, the Agreement is ratified and
confirmed in all respects.

         IN WITNESS WHEREOF, the Company and the Rights Agent have executed this
Amendment as of March 6, 2000.

[corporate seal]                           K-TRON INTERNATIONAL, INC.

Attest:

 /s/ Mary E. Vaccara                       By:  /s/ Edward B. Cloues, II
---------------------                           --------------------------
Mary E. Vaccara                                 Edward B. Cloues, II
As its Secretary                                As its Chairman of the Board
                                                and Chief Executive Officer

                                            AMERICAN STOCK TRANSFER
                                            & TRUST COMPANY



                                            By: /s/ Isaac Kagan
                                               -----------------------
                                               Isaac Kagan
                                               As its Vice President


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