EXHIBIT 10.72

                                                                  EXECUTION COPY
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------

                          FIRST SUPPLEMENTAL INDENTURE

                            DATED AS OF JUNE 28, 1999

                                       to

                                    INDENTURE

                            dated as of June 28, 1999

                                     between

                              EDISON MISSION ENERGY

                                       and

                              THE BANK OF NEW YORK,

                                   as Trustee

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





                  FIRST SUPPLEMENTAL INDENTURE, dated as of June 28, 1999 (this
"FIRST SUPPLEMENTAL INDENTURE"), to the Indenture, dated as of June 28, 1999
(the "ORIGINAL INDENTURE"), between EDISON MISSION ENERGY, a California
corporation (the "COMPANY"), and THE BANK OF NEW YORK, a New York banking
corporation (the "TRUSTEE").

                  WHEREAS, the Company and the Trustee have heretofore executed
and delivered the Original Indenture to provide for the issuance from time to
time of Notes (as defined in the Original Indenture) of the Company, to be
issued in one or more series;

                  WHEREAS, SECTIONS 2.1, 2.2 and 7.1 of the Original Indenture
provide, among other things, that the Company and the Trustee may enter into
indentures supplemental to the Original Indenture for, among other things, the
purpose of establishing the designation, form, terms and provisions of Notes of
any series as permitted by SECTIONS 2.1, 2.2 and 7.1 of the Original Indenture;

                  WHEREAS, the Company (i) desires the issuance of a series of
Notes to be designated as hereinafter provided and (ii) has requested the
Trustee to enter into this First Supplemental Indenture for the purpose of
establishing the designation, form, terms and provisions of the Notes of such
series;

                  WHEREAS, all action on the part of the Company necessary to
authorize the issuance of said Notes under the Original Indenture and this First
Supplemental Indenture (the Original Indenture, as supplemented by this First
Supplemental Indenture, being hereinafter called the "INDENTURE") has been duly
taken.

                  NOW, THEREFORE, THIS FIRST SUPPLEMENTAL INDENTURE

WITNESSETH:

                  That, in order to establish the designation, form, terms and
provisions of, and to authorize the authentication and delivery of, said Notes,
and in consideration of the acceptance of said Notes by the Holders thereof and
of other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the parties hereto hereby agree as follows:

                                   ARTICLE I.

                                   DEFINITIONS
                                   -----------

                  (a) Capitalized terms used herein and not otherwise defined
herein shall have the respective meanings ascribed thereto in the Original
Indenture.

                  (b) The rules of interpretation set forth in the Original
Indenture shall be applied hereto as if set forth in full herein.







                  (c) For all purposes of this First Supplemental Indenture,
except as otherwise expressly provided or unless the context otherwise requires,
the following terms shall have the following respective meanings (such meanings
shall apply equally to both the singular and plural forms of the respective
terms):

                  "COMPARABLE TREASURY ISSUE" means the United States Treasury
security selected by Credit Suisse First Boston Corporation or an affiliate as
having a maturity comparable to the remaining term of the Notes that would be
utilized, at the time of selection and in accordance with customary financial
practice, in pricing new issues of corporate debt securities of comparable
maturity to the remaining term of the Notes.

                  "COMPARABLE TREASURY PRICE" means the average of three
Reference Treasury Dealer Quotations obtained by the Trustee in respect of the
Notes to be redeemed on the applicable redemption date.

                  "REFERENCE TREASURY DEALER QUOTATION" means, with respect to
each Reference Treasury Dealer and any redemption date, the average, as
determined by the Trustee, of the bid and asked prices for the Comparable
Treasury Issue (expressed in each case as a percentage of its principal amount)
quoted in writing to the Trustee by a Reference Treasury Dealer at 3:30 p.m.,
New York City time, on the third Business day preceding the redemption date.

                  "REFERENCE TREASURY DEALERS" means Credit Suisse First Boston
Corporation (so long as it continues to be a primary U.S. Government securities
dealer) and any two other primary U.S. Government securities dealers chosen by
the Company. If Credit Suisse First Boston Corporation ceases to be a primary
U.S. Government securities dealer, the Company will appoint in its place another
nationally recognized investment banking firm that is a primary U.S. Government
securities dealer.

                  "REMAINING SCHEDULED PAYMENTS" means, with respect to each
Note that the Company is redeeming, the remaining scheduled payments of the
principal and interest that would be due after the related redemption date if
such Note were not redeemed. However, if the redemption date is not a scheduled
interest payment date with respect to that Note, the amount of the next
succeeding scheduled interest payment on that Note will be reduced by the amount
of interest accrued on such Note to the redemption date.

                  "SERIES A NOTES" shall have the meaning ascribed thereto in
SECTION 2.1(a) hereof.

                  "TREASURY RATE" means, with respect to any redemption date, an
annual rate equal to the semiannual equivalent yield to maturity of the
Comparable Treasury Issue, assuming a price for the Comparable Treasure Issue
(expressed as a percentage of its principal amount) equal to the Comparable
Treasury Price for the redemption date. The semiannual equivalent yield to
maturity will be computed as of the third business day immediately preceding the
redemption date.







                                   ARTICLE II.

                             THE TERMS OF THE NOTES
                             ----------------------

           SECTION 2.1. TERMS OF 7.73% SENIOR NOTES DUE JUNE 15, 2009.
                        ---------------------------------------------

           (a) There is hereby created one series of Notes designated:
7.73% Senior Notes due June 15, 2009, in the aggregate principal amount of
$600,000,000 (the "SERIES A NOTES"). The Series A Notes may forthwith be
executed by the Company and delivered to the Trustee for authentication and
delivery by the Trustee in accordance with the provisions of SECTION 2.3 of the
Original Indenture.

                  (b) Each of the Series A Notes shall have and be subject to
such other terms as provided in the Indenture and shall be evidenced by one or
more Notes in the form of EXHIBIT A to the Indenture.

                  SECTION 2.2.  INTEREST AND PRINCIPAL.
                                ----------------------

                  The Series A Notes will mature on June 15, 2009 and will bear
interest at the rate of 7.73% per annum. The Company will pay interest on the
Series A Notes on each June 15 and December 15, beginning on December 15, 1999,
to the holders of record on the immediately preceding June 1 or December 1.
Interest on the Series A Notes shall accrue from the most recent date to which
interest has been paid or, if no interest has been paid, from June 28, 1999.

                  SECTION 2.3.  REDEMPTION.
                                -----------

                  The Company at its option may, at any time, redeem the Series
A Notes, in whole or in part, upon payment of a redemption price equal to (A)
the greater of (i) 100% of the principal amount of the Series A Notes to be
redeemed and (ii) the sum of present values of the Remaining Scheduled Payments
on the Series A Notes being redeemed discounted to the date of redemption on a
semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at
a rate equal to the Treasury Rate plus 37.5 basis points, plus (B) accrued and
unpaid interest, if any, on the principal amount of Notes being redeemed to the
redemption date.







                                  ARTICLE III.

                                  MISCELLANEOUS
                                  -------------

                SECTION 3.1. EXECUTION OF SUPPLEMENTAL INDENTURE.
                             -----------------------------------

                  This First Supplemental Indenture is executed and shall be
construed as an indenture supplemental to the Original Indenture and, as
provided in the Original Indenture, this First Supplemental Indenture forms a
part thereof.

                  SECTION 3.2.  CONCERNING THE TRUSTEE.
                                ----------------------

                  The recitals contained herein and in the Series A Notes,
except with respect to the Trustee's certificates of authentication, shall be
taken as the statements of the Company, and the Trustee assumes no
responsibility for the correctness of the same. The Trustee makes no
representations as to the validity or sufficiency of this First Supplemental
Indenture or of the Series A Notes.

                  SECTION 3.3.  COUNTERPARTS.
                                ------------

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

                  SECTION 3.4.  GOVERNING LAW.
                                -------------

                  THIS FIRST SUPPLEMENTAL INDENTURE AND EACH NOTE OF THE SERIES
CREATED HEREUNDER SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE
LAWS OF THE STATE OF NEW YORK.






                  IN WITNESS WHEREOF, the parties have caused this First
Supplemental Indenture to be duly executed by their respective officers
thereunto duly authorized as of the date first above written.

                                      EDISON MISSION ENERGY

                                      By: /s/ Steven D. Eisenberg
                                          -----------------------
                                          Name:     Steven D. Eisenberg
                                          Title:    Vice President and Associate
                                                    General Counsel

                                      THE BANK OF NEW YORK, as Trustee

                                      By: /s/ Mary Beth Lewicki
                                          ---------------------
                                          Name:     Mary Beth Lewicki
                                          Title:    Assistant Vice President