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Exhibit 2.3


FRESENIUS AKTIENGESELLSCHAFT


ELSE-KRÖNER STRASSE 1


61352 BAD HOMBURG v.d.H.


GERMANY




























Aktiengesellschaft Kommanditgesellschaft auf
Aktien Amstgericht  






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Definitions




| |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
| | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| | (a) Extraordinary Transaction means
    (i) any merger, consolidation, sale of all or substantially
    all assets, recapitalization, other business combination,
    liquidation, or other similar action out of the ordinary course
    of business of FMC KGaA, (ii) any issuance of ordinary
    shares of FMC KGaA representing more than 10% of the total FMC
    KGaA ordinary shares outstanding, or (iii) any amendment of
    the organizational documents of FMC KGaA that adversely affects
    any holders of FMC KGaA ordinary shares or FMC KGaA preference
    shares in their capacities as such holders.
|
| | (b) GP Board means the supervisory board
    (Aufsichtsrat) of FMC Management AG.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
|
| | (c) GP Independent Director means a
    member of the GP Board without a substantial business or
    professional relationship with any of FMC AG, FMC KGaA,
    Fresenius AG, FMC Management AG, or any Affiliate of any of the
    foregoing, other than as a member of the GP Board, the KGaA
    Board, or both.                                                                                                                                                                                                                                                                                                      
|
| | (d) KGaA Board means the supervisory
    board (Aufsichtsrat) of FMC KGaA.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|
| | (e) Non-Employee Director means a member
    of the GP Board, as the context shall require, other than any
    such member representing employees pursuant to German
    co-determination laws or works council constitution laws.                                                                                                                                                                                                                                                                                                                                                                                        

GP Independent Directors;
Compliance with Laws




| |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
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| | (a) During the term of this Agreement, the ratio of GP
    Independent Directors to all Non-Employee Directors shall be not
    less than one-third, and there shall be at least two GP
    Independent Directors at all times. If any person serving as a
    GP Independent Director shall resign, be removed or otherwise be
    unable or unwilling to serve in such capacity, a new person
    shall be appointed to serve as a GP Independent Director in
    accordance with the Articles of Association of FMC Management
    AG, this Agreement and applicable law if, as a result of such
    resignation or removal, the number of GP Independent Directors
    falls below the minimum number required by this paragraph. Each
    GP Independent Director shall be afforded all rights of
    information, access and participation with respect to the
    business and affairs of FMC KGaA and the management of such
    business and affairs by FMC Management AG as are afforded any
    other GP Director, and shall be afforded contemporaneous English
    translations of minutes of all meetings of the GP Board (or any
    committee thereof) and such other documents as may be advisable
    or requested in connection with the performance of their duties.
|
| | (b) During the term of this Agreement, if the GP Board
    shall establish any committees thereof, Fresenius AG will use
    its best efforts as the sole shareholder of FMC Management AG to
    cause the ratio of GP Independent Directors to Non-Employee
    Directors appointed to any such committee to be not less than
    one-third and to cause at least one GP Independent Director to
    be appointed at all times to any such committee; it being
    understood that, except as required by applicable law
    (including, but not limited to the Sarbanes-Oxley Act of 2002),
    committees shall be formed by the GP Board in its sole
    discretion.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|
| | (c) During the term of this Agreement, Fresenius AG
    undertakes to exercise all rights as the sole shareholder of FMC
    Management AG, and to cause FMC Management AG to exercise all
    rights as the sole general partner of FMC KGaA, in a manner
    consistent with, and in order to effect the provisions of,
    sections 2.1(a) and 2.1(b).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
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| | (d) During the term of this Agreement, Fresenius AG shall
    comply, and shall cause FMC Management AG and the other
    Affiliates of Fresenius AG to comply, with all provisions of
    German law applicable to Extraordinary Transactions.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         

Interested Transactions




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provided


Listing of American
Depositary Shares; SEC Filings




| |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
| | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| | (a) maintain in effect a deposit agreement for the ordinary
    shares of FMC KGaA and, if the preference shares of FMC KGaA are
    eligible for listing on the New York Stock Exchange, the
    preference shares of FMC KGaA and the listing of American
    Depositary Shares (ADSs) representing the ordinary
    shares and, subject to satisfaction of applicable listing
    requirements, the preference shares of FMC KGaA on either the
    New York Stock Exchange or the Nasdaq Stock Market;                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|
| | (b) file (or, if permitted by the rules of the SEC,
    furnish) all Securities Filings required by the exchange or
    other market on which ADSs of FMC KGaA are listed, and by the
    1933 Act, the 1934 Act, and other applicable laws;                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|
| | (c) prepare all financial statements required to be
    included in any Securities Filings in accordance with US GAAP;                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
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| | (d) on an annual basis, prepare audited consolidated
    financial statements including, without limitation, a balance
    sheet, a statement of operations and a statement of cash flows,
    and all appropriate notes, all in accordance with US GAAP and,
    on a quarterly basis, prepare and furnish to the SEC
    consolidated financial statements prepared in accordance with US
    GAAP under cover of form 6-K or a comparable successor form;                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
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| | (e) in connection with any exercise of voting or consent
    rights by holders of a class of shares registered under
    Section 12 of the 1934 Act, or ADSs representing any such
    class of shares, furnish to the SEC under cover of Form 6-K
    materials relating to the solicitation of voting instructions
    from holders of ADSs with respect to the matter or matters to be
    voted on, and make such materials available to the depositary
    under the deposit agreement(s) for distribution to holders of
    American Depositary Receipts (ADRs) evidencing such
    ADSs, such materials to include information generally comparable
    to that which would be included in proxy materials prepared in
    accordance with Regulation 14A under the 1934 Act; provided
    that such materials need include only such information
    concerning (i) the beneficial ownership of FMC KGaAs
    outstanding voting securities, (ii) the trading market for
    and the price of such securities, (iii) the directors and
    officers of FMC KGaA, (iv) compensation of directors and
    officers of FMC KGaA and compensation plans relating thereto,
    (v) options to purchase securities of FMC KGaA of a class
    registered under the 1934 Act and (vi) material
    transactions between FMC KGaA and its subsidiaries and directors
    and officers of FMC KGaA, controlling persons of FMC KGaA, and
    relatives or spouses of such directors, officers and controlling
    persons as would be required to be provided by the applicable
    items of an annual report on
    Form 20-F under
    the 1934 Act, or any successor form, as in effect from time to
    time: and
|
| | (f) make available to the depositary under the deposit
    agreement(s) for distribution to holders of ADRs on an annual
    basis, a copy of any report prepared by the KGaA Board and
    provided to the shareholders of FMC KGaA generally pursuant to
    Section 314(2) of the German Stock Corporation Law (or any
    successor                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                



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| |                                                                                                                                                   
| | --------------------------------------------------------------------------------------------------------------------------------------------------
| | provision) concerning the results of its examination of the
    managing board report on the relations of FMC KGaA with
    connected enterprises.

Directors and Officers
Insurance


Duration and Amendment Effective Date




| |                                                    
| | ---------------------------------------------------
| | (b) Termination. This Agreement shall terminate if:



| |                                                                                                                                                                                                                                                                                                                              
| | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| | (i) Fresenius AG or its Affiliates acquire all of the
    voting shares of FMC KGaA;                                                                                                                                                                                                                                         
|
| | (ii) Fresenius AGs beneficial ownership (as defined
    in
    Regulation 13D-G
    under the 1934 Act) is reduced to 25% or less of the share
    capital of FMC KGaA;                                                                                                                                                     
|
| | (iii) Fresenius AG or an Affiliate of Fresenius AG ceases
    to own the general partner interest of FMC KGaA; or                                                                                                                                                                                                            
|
| | (iv) FMC KGaA no longer meets the minimum threshold for
    obligatory registration of its ordinary shares or ADSs
    representing its ordinary shares or its preference shares or
    ADSs representing its preference shares, as applicable, under
    Section 12(g)(1) of the 1934 Act and
    Rule 12g-1
    thereunder.



| |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
| | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| | (c) Termination; Amendment. This Agreement may be
    terminated or amended by mutual consent of FMC KGaA and a
    majority of the GP Independent Directors, providedthat
    beneficial owners of 75% of the FMC KGaA ordinary shares held by
    shareholders other than Fresenius AG and its Affiliates
    represented at a general meeting of shareholders and 75% of the
    preference shares represented at a general meeting of preference
    shareholders, as applicable, approve such termination or
    amendment. Any such amendment must be in writing and signed by
    or on behalf of Fresenius AG, FMC Management AG, and the GP
    Independent Directors.

Miscellaneous forum non conveniens








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| |                  
| | -----------------
| | Very truly yours,
|
| | FRESENIUS AG     



| |     | 
| | --- | 
| | By: | 

| |                                      
| | -------------------------------------
| |                                      
| | Name:                                
| | Title: Member of the Management Board



| |     | 
| | --- | 
| | By: | 

| |                                                                                                                                                                                                                                        
| | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| |                                                                                                                                                                                                                                        
| | Name:                                                                                                                                                                                                                                  
| | Title: Member of the Management Board                                                                                                                                                                                                  
|
| | FRESENIUS MEDICAL CARE MANAGEMENT AG, for itself and as
    General Partner of Fresenius Medical Care AG & Co. KGaA, a
    partnership limited by shares created upon the transformation of
    legal form of Fresenius Medical Care AG



| |     | 
| | --- | 
| | By: | 

| |                                      
| | -------------------------------------
| |                                      
| | Name:                                
| | Title: Member of the Management Board



| |     | 
| | --- | 
| | By: | 

| |                                      
| | -------------------------------------
| |                                      
| | Name:                                
| | Title: Member of the Management Board
|
| |                                      
| | Walter L. Weisman                    
|
| |                                      
| | John G. Kringel