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                                                                    EXHIBIT 4.10
 
     SUPPLEMENTAL INDENTURE, dated as of September 11, 1998, by and between
MARINER HEALTH GROUP, INC., a Delaware corporation (the "Company"), and STATE
STREET BANK AND TRUST COMPANY, as trustee (the "Trustee").

                             W I T N E S S E T H:
                             - - - - - - - - - - 

  WHEREAS, the Company and Trustee have heretofore executed and delivered an
Indenture, dated as of April 4, 1996 (the "Indenture"), providing for the
issuance of $150,000,000 in aggregate principal amount of 9-1/2% Senior
Subordinated Notes due 2006 (the "Securities") of the Company;

  WHEREAS, Section 901 of the Indenture provides that the Company and the
Trustee may, without the consent of the Holders, the Guarantors (if any) or any
other obligor upon the securities, when authorized by a resolution of its Board
of Directors and when the interests of the Holders shall not be adversely
affected, enter into a supplemental indenture, in form and substance
satisfactory to the Trustee, for the purpose of amending the Indenture to
supplement any provisions with respect to matters arising under the Indenture;

  WHEREAS, Section 1015 of the Indenture requires the Company, upon any Change
of Control, to offer to purchase the Securities from any Holder for cash at the
Change of Control Purchase Price and to purchase any Securities tendered
according to the terms of such offer;

  WHEREAS, the Company wishes to amend Section 1015 of the Indenture to permit
the Company, upon a Change of Control, to either (1) purchase tendered
Securities for cash at the Change of Control Purchase Price or (2) cause a
person or entity other than the Company to purchase such Securities for cash at
the Change of Control Purchase Price at the option of the Company;

  WHEREAS, the Company and the Trustee have determined that the interests of the
Holders will not be adversely affected by this Supplemental Indenture;

  WHEREAS, the Company has been authorized by a resolution of its Board of
Directors to enter into this Supplemental Indenture;

  WHEREAS, all other acts and proceedings required by law, by the Indenture and
by the certificate of incorporation (as amended to this date) and by-laws (as
amended to this date) of the Company to make this Supplemental Indenture a valid
and binding agreement for the purposes expressed herein, in accordance with its
terms, have been duly done and performed;

  NOW, THEREFORE, in consideration of the premises and the covenants and
agreements contained herein, and for other good and valuable consideration, the
receipt and
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sufficiency of which is hereby acknowledged, and for the equal and proportionate
benefit of the Holders of the Securities, the Company and the Trustee hereby
agree as follows:

                                  ARTICLE I.

  Definitions.
  ----------- 

  Capitalized terms used in this Supplemental Indenture and not otherwise
defined herein shall have the meanings assigned to such terms in the Indenture.

                                  ARTICLE II.

Section 1.  Amendment of Section 101 (Definitions).
            ---------------------------------------

  Section 101 of the Indenture is hereby amended by inserting the following new
definitions in their appropriate alphabetical order:

          "`Alternate Transaction' shall have the meaning ascribed thereto in
            ---------------------                                            
     Section 1015 of this Indenture."

          "`Company Transaction' shall have the meaning ascribed thereto in
            -------------------                                            
     Section 1015 of this Indenture."

          "`Designated Purchaser' shall have the meaning ascribed thereto in
            --------------------
     Section 1015 of this Indenture."

Section 2.  Amendment of Section 1015 (Purchase of Securities Upon Change of
            ----------------------------------------------------------------
            Control).
            -------- 

  The provisions of Section 1015 of the Indenture are hereby amended by deleting
the text of such Section 1015 in its entirety and inserting in lieu thereof the
following:


          "Section 1015.  Purchase of Securities upon a Change of Control.
                          ----------------------------------------------- 

         (a) If a Change of Control shall occur at any time, then each Holder
    shall have the right to require that the Company either (1) purchase (the
    "Company Transaction") or (2) cause another person or entity designated by
    the Company (the "Designated Purchaser") to purchase (the "Alternate
    Transaction") such Holder's Securities in whole or in part in integral
    multiples of $1,000, at a purchase price (the "Change of Control Purchase
    Price") in cash in an amount equal to 101% of the principal amount of such
    Securities, plus accrued and unpaid interest, if any, to the date of
    purchase (the "Change of Control Purchase Date"), pursuant to the offer
    described below in this Section 1015 (the "Change of Control Offer") and in
    accordance with the other procedures set forth in Subsections (b), (c), (d)
    and (e) of this Section 1015.

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         (b) Within 30 days following any Change of Control, the Company shall
    notify the Trustee thereof and give written notice (a "Change of Control
    Purchase Notice") of such Change of Control to each Holder, by first-class
    mail, postage prepaid, at his address appearing in the Security Register,
    stating, among other things:


               (1) that a Change of Control has occurred, the date of such
          event, and that such Holder has the right to require the Company to
          repurchase such Holder's Securities at the Change of Control Purchase
          Price;

               (2) the circumstances and relevant facts regarding such Change of
          Control (including but not limited to information with respect to pro
          forma historical income, cash flow and capitalization after giving
          effect to such Change of Control);

               (3) (i) the most recently filed Annual Report on Form 10-K
          (including audited consolidated financial statements) of the Company,
          the most recent subsequently filed Quarterly Report on Form 10-Q, as
          applicable, and any Current Report on Form 8-K of the Company filed
          subsequent to such Quarterly Report (or in the event the Company is
          not required to prepare any of the foregoing Forms, the comparable
          information required to be prepared by the Company and any Guarantor
          pursuant to Section 1018), (ii) a description of material
          developments, if any, in the Company's business subsequent to the date
          of the latest of such reports and (iii) such other information, if
          any, concerning the business of the Company ,which the Company in good
          faith believes will enable such Holders to make an informed investment
          decision regarding the Change of Control Offer;

               (4) that the Change of Control Offer is being made pursuant to
          this Section 1015 and that all Securities properly tendered pursuant
          to the Change of Control Offer will be accepted for payment at the
          Change of Control Purchase Price;

               (5) the Change of Control Purchase Date, which shall be a
          Business Day no earlier than 30 days nor later than 60 days from the
          date such notice is mailed, or such later date as is necessary to
          comply with requirements under the Exchange Act;

               (6) the Change of Control Purchase Price;

               (7) the names and addresses of the Paying Agent and the offices
          or agencies referred to in Section 1002;

                                      -3-
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               (8) that Securities must be surrendered on or prior to the Change
          of Control Purchase Date to the Paying Agent at the office of the
          Paying Agent or to an office or agency referred to in Section 1002 to
          collect payment;

               (9) that the Change of Control Purchase Price for any Security
          which has been properly tendered and not withdrawn will be paid
          promptly following the Change of Control Offer Purchase Date;

               (10) the procedures that a Holder must follow to accept a Change
          of Control Offer or to withdraw such acceptance;

               (11) that any Security not tendered will continue to accrue
          interest; and

               (12) that, unless the Company defaults in the payment of the
          Change of Control Purchase Price, any Securities accepted for payment
          pursuant to the Change of Control Offer shall cease to accrue interest
          after the Change of Control Purchase Date.



         (c) Upon receipt by the Company of the proper tender of Securities, the
    Holder of the Security in respect of which such proper tender was made shall
    (unless the tender of such Security is properly withdrawn) thereafter be
    entitled to receive solely the Change of Control Purchase Price with respect
    to such Security.  Upon surrender of any such Security for purchase in
    accordance with the foregoing provisions, such Security shall be purchased
    by, (a) with respect to each Company Transaction, the Company and, (b) with
    respect to each Alternate Transaction, the Designated Purchaser, in each
    case, at the Change of Control Purchase Price, provided, however, that
    installments of interest whose Stated Maturity is on the Change of Control
    Purchase Date shall be payable to the Holders of such Securities, or one or
    more Predecessor Securities, registered as such on the relevant Regular
    Record Dates according to the terms and the provisions of Section 309;
    provided, further, that notwithstanding anything herein to the contrary, any
    Security which is purchased by a Designated Purchaser shall continue to bear
    interest at the rate born by the Security until paid in full in accordance
    with the terms herein.  If any Security tendered for purchase in accordance
    with the provisions of this Section 1015 shall not be so paid or purchased
    upon surrender thereof, the principal thereof (and premium, if any, thereon)
    shall, until paid, bear interest from the Change of Control Purchase Date at
    the rate borne by such Security.  Holders electing to have Securities
    purchased will be required to surrender such Securities to the Paying Agent
    at the address specified in the Change of Control Purchase Notice at least
    one Business Day prior to the Change of Control Purchase Date. Any Security
    that is to be purchased only in part shall be surrendered to a Paying Agent
    at the office of such Paying Agent (with, if the Company, the Security
    Registrar or the Trustee so requires, due endorsement by, or a written

                                      -4-
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    instrument of transfer in form satisfactory to the Company and the Security
    Registrar or the Trustee, as the case may be, duly executed by the Holder
    thereof or such Holder's attorney duly authorized in writing), and the
    Company shall execute and the Trustee shall authenticate and deliver to the
    Holder of such Security, without service charge, one or more new Securities
    of any authorized denomination as requested by such Holder in an aggregate
    principal amount equal to, and in exchange for, the portion of the principal
    amount of the Security so surrendered that is not purchased.

         (d) The Company shall (i) not later than the Change of Control Purchase
    Date, either (A) cause a Designated Purchaser to accept for purchase
    Securities or portions thereof tendered pursuant to the Change of Control
    Offer or (B) accept for payment Securities or portions thereof tendered
    pursuant to the Change of Control Offer, (ii) not later than 10:00 a.m. (New
    York time) on the Change of Control Purchase Date, deposit with the Trustee
    or with a Paying Agent (or, in the case of an Alternate Transaction, cause
    the Designated Purchaser to deposit with the Trustee or with a Paying Agent)
    an amount of money in same day funds (or New York Clearing House funds if
    such deposit is made prior to the Change of Control Purchase Date)
    sufficient to pay the aggregate Change of Control Purchase Price of all the
    Securities or portions thereof which are to be purchased (whether by the
    Company or a Designated Purchaser) as of the Change of Control Purchase
    Date, and (iii) not later than 10:00 a.m. (New York time) on the Change of
    Control Purchase Date deliver to the Paying Agent an Officers' Certificate
    stating the Securities or portions thereof accepted for payment by, (1) with
    respect to each Company Transaction, the Company and, (2) with respect to
    each Alternate Transaction, the Designated Purchaser.  The Paying Agent
    shall promptly mail or deliver to Holders of Securities so accepted payment
    in an amount equal to the Change of Control Purchase Price of the Securities
    purchased from each such Holder, and the Company shall execute and the
    Trustee shall promptly authenticate and mail or deliver to (x) such Holders
    a new Security equal in principal amount to any unpurchased portion of the
    Security surrendered and (y) any Designated Purchaser a new Security equal
    in principal amount to the Securities purchased by such Designated
    Purchaser.  Any Securities not so accepted shall be promptly mailed or
    delivered by the Paying Agent at the Company's expense to the Holder
    thereof.  The Company will publicly announce the results of the Change of
    Control Offer on the Change of Control Purchase Date.  For purposes of this
    Section 1015 the Company shall choose a Paying Agent which shall not be the
    Company.  In the event that any Designated Purchaser fails to provide funds
    with respect to any Securities tendered hereunder, the Company shall remain
    liable with respect thereto for the payment of the Change of Control
    Purchase Price and the interest on such Securities until the Change of
    Control Purchase Price is paid to such Holder. Notwithstanding anything
    herein to the contrary, the Indebtedness evidenced by the Securities
    purchased by a Designated Purchaser shall not be deemed to have been
    accepted for payment by the Company, not be extinguished by virtue of such
    purchase and such Securities continue to bear interest at the rate borne by
    such Security.

                                      -5-
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         (e) A tender made in response to a Change of Control Purchase Notice
    may be withdrawn if the Company receives, not later than one Business Day
    prior to the Change of Control Purchase Date, a telegram, telex, facsimile
    transmission or letter, specifying, as applicable:

               (1) the name of the Holder:

               (2) the certificate number of the Security in respect of which
          such notice of withdrawal is being submitted,

               (3) the principal amount of the Security (which shall be $1,000
          or an integral multiple thereof) delivered for purchase by the Holder
          as to which such notice of withdrawal is being submitted;

               (4) a statement that such Holder is withdrawing his election to
          have such principal amount of such Security purchased; and

               (5) the principal amount, if any, of such Security (which shall
          be $1,000 or an integral multiple thereof) that remains subject to the
          original Change of Control Purchase Notice and that has been or will
          be delivered for purchase by the Company.

         (f) Subject to applicable escheat laws, the Trustee and the Paying
    Agent shall return to the Company any cash that remains unclaimed, together
    with interest or dividends, if any, thereon, held by them for the payment of
    the Change of Control Purchase Price; provided, however, that, (x) to the
    extent that the aggregate amount of cash deposited by the Company, pursuant
    to clause (ii) of paragraph (d) above exceeds the aggregate Change of
    Control Purchase Price of the Securities or portions thereof to be
    purchased, then the Trustee shall hold such excess for the Company and (y)
    unless otherwise directed by the Company in writing, promptly after the
    Business Day following the Change of Control Purchase Date the Trustee shall
    return any such excess to the Company together with interest or dividends,
    if any, thereon.

         (g) The Company and the Designated Purchaser, if any, shall comply, to
    the extent applicable, with the applicable tender offer rules, including
    Rule 14e- I under the Exchange Act and any other applicable securities laws
    or regulations in connection with a Change of Control Offer."

                                      -6-
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                                  ARTICLE III

Section 1.  Continuing Effect of Indenture.
            ------------------------------ 

  Except as expressly provided herein, all of the terms, provisions and
conditions of the Indenture and the Securities outstanding thereunder shall
remain in full force and effect.

Section 2.  Construction of Supplemental Indenture.
            -------------------------------------- 

  This Supplemental Indenture is executed as, and shall constitute, an indenture
supplemental to the Indenture and shall be construed in connection with and as
part of the Indenture.  This Supplemental Indenture shall be governed by and
construed in accordance with the laws of the State of New York.

Section 3.  Trust Indenture Act Controls.
            ---------------------------- 

  If any provision of this Supplemental Indenture limits, qualifies or conflicts
with another provision of this Supplemental Indenture or the Indenture that is
required to be included by the Trust Indenture Act of 1939 as in force at the
date as of which this Supplemental Indenture is executed, the provision required
by said Act shall control.

Section 4.  Trustee Disclaimer.
            ------------------ 

  The recitals contained in this Supplemental Indenture shall be taken as the
statements of the Company, and the Trustee assumes no responsibility for their
correctness.  The Trustee makes no representations as to the validity or
sufficiency of this Supplemental Indenture.

Section 5.  Counterparts.
            ------------ 

  This Supplemental Indenture may be executed in any number of counterparts,
each of which so executed shall be deemed to be an original, but all such
counterparts shall together constitute but one and the same instrument.

                  [Remainder of Page Intentionally Left Blank]

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  IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture
to be duly executed, and their respective corporate seals to be hereunto affixed
and attested, all as of the day and year first above written.


                                             MARINER HEALTH GROUP, INC.


                                             By:  /s/ Boyd P. Gentry
                                                  -----------------------------

                                                  Name: Boyd P. Gentry
                                                        ----------------------- 
                                                  Title: Vice President and
                                                          Treasurer
                                                        -----------------------
 
                                             [SEAL]


                                             Attest:  /s/ Stefano M. Miele
                                                      -------------------------
                                                      Name: Stefano M. Miele
                                                           --------------------
                                                      Title: Vice President and
                                                              Associate General
                                                              Counsel
                                                           --------------------

                                             STATE STREET BANK AND TRUST
                                             COMPANY, as Trustee


                                             By:  /s/ M.L. Stores
                                                  -----------------------------

                                                  Name:  M.L. Stores
                                                        ----------------------- 
                                                  Title: Vice President
                                                        -----------------------
                                             [SEAL]

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