Document:

<PAGE>

                                                               Exhibit 10.59.1

                                                                EXECUTION COPY

     AMENDMENT NO. 1, dated as of May 27, 1999 (this "AMENDMENT"), to the
Credit Support Guarantee, dated as of March 18, 1999, (the "GUARANTEE") made
by EDISON MISSION ENERGY, a California corporation (the "GUARANTOR"), in
favor of UNITED STATES TRUST COMPANY OF NEW YORK, as Collateral Agent for
certain senior secured creditors of the Borrower (in such capacity, the
"COLLATERAL AGENT").

                                   RECITALS

          A. Edison Mission Holdings Co. (the "BORROWER") has entered into a
Credit Agreement, dated as of March 18, 1999 (as the same may be amended,
supplemented or otherwise modified from time to time, the "CREDIT AGREEMENT",
the loans made thereunder, the "LOANS"), with certain financial institutions
(collectively, the "LENDERS") and Citicorp USA, Inc., as administrative agent
for the Lenders (in such capacity, the "ADMINISTRATIVE AGENT").

          B. Pursuant to the Guarantee, the Guarantor has provided credit
support for the Borrower's senior secured indebtedness in the form of a
guarantee in the amount of $35 million.

          C. The Borrower wishes to issue $300 million in aggregate principal
amount of Senior Secured Bonds due 2019 and $530 million in aggregate
principal amount of Senior Secured Bonds due 2026 (collectively, the "BONDS";
the trustee to the holders thereof, the "TRUSTEE"), the proceeds of which
will be used to refinance a portion of the Loans and to repay a portion of
the Guarantor's equity investment in the Borrower.

          D. To meet the requirements of Section 8.2.1(e) of the Credit
Agreement, the Guarantor has requested, and, upon this Amendment becoming
effective, the Collateral Agent has agreed, that the amount of the guarantee
provided for in the Guarantee be amended in the manner provided for in this
Amendment.

     NOW, THEREFORE, the parties hereto hereby agree as follows:

          1. AMENDMENT OF DEFINITIONS. The definition of the term "Guarantee
Cap" contained in Section 1(b) of the Guarantee is hereby amended by deleting
the current definition in its entirety and substituting in lieu thereof the
following:

          "GUARANTEE CAP" means forty-two million U.S. Dollars
(U.S.$42,000,000).

          2. COUNTERPARTS. This Amendment may be executed by the parties
hereto in any number of separate counterparts, and all of said counterparts
taken together shall be deemed to

<PAGE>
                                                                              2

constitute one and the same instrument. Delivery of an executed counterpart
of a signature page to this letter by facsimile shall be effective as
delivery of a manually executed counterpart of this Amendment.

          3. LIMITED EFFECT. Except as expressly provided herein, all of the
terms and provisions of the Guarantee are and shall remain in full force and
effect.

          4. SEVERABILITY. Any provision of this Amendment which is
prohibited or unenforceable in any jurisdiction shall, as to such
jurisdiction, be ineffective to the extent of such prohibition or
unenforceability without invalidating the remaining provisions hereof, and
any such prohibition or unenforceability in any jurisdiction shall not
invalidate or render unenforceable such provision in any other jurisdiction.

          5. CONDITIONS TO EFFECTIVENESS. The amendment provided for herein
shall become effective on the date the Collateral Agent shall have received
counterparts of this Amendment duly executed and delivered by the Guarantor
and consented to by the Administrative Agent and the Trustee.

          6. APPLICABLE LAW. THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF
THE PARTIES HERETO SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN
ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

<PAGE>

                                                                             3

          IN WITNESS WHEREOF, the parties hereto have caused this Amendment
to be duly executed and delivered by their respective proper and duly
authorized officers as of the day and year first above written.

                                                EDISON MISSION ENERGY

                                             By: /s/ Steven D. Eisenberg
                                                ------------------------------
                                                Name:  Steven D. Eisenberg
                                                Title: Vice President

                                             UNITED STATES TRUST COMPANY OF
                                             NEW YORK, as Collateral Agent

                                             By: /s/ Christopher J. Grell
                                                ------------------------------
                                                Name:  Christopher J. Grell
                                                Title: Assistant Vice President

Acknowledged and Consented to by:

CITICORP USA, INC., as Administrative Agent

By: /s/ Anita J. Brickell
   ---------------------------------
   Name:  Anita J. Brickell
   Title: Attorney-In-Fact

UNITED STATES TRUST COMPANY OF NEW YORK, as Trustee

By: /s/ Christopher J. Grell
   ---------------------------------
   Name:  Christopher J. Grell
   Title: Assistant Vice President<PAGE>

                                                               Exhibit 10.60.1

                                                                EXECUTION COPY

     AMENDMENT NO. 1, dated as of May 27, 1999 (this "AMENDMENT"), to the
Debt Service Reserve Guarantee, dated as of March 18, 1999 (the "GUARANTEE"),
made by EDISON MISSION ENERGY, a California corporation (the "GUARANTOR"), in
favor of UNITED STATES TRUST COMPANY OF NEW YORK, as Collateral Agent (in
such capacity, the "COLLATERAL AGENT") for certain senior secured creditors
of Edison Mission Holdings Co., a California corporation (the "BORROWER").

                                 RECITALS

          A. The Borrower has entered into a Credit Agreement, dated as of
March 18, 1999 (as the same may be amended, supplemented or otherwise
modified from time to time, the "CREDIT AGREEMENT"; the loans made
thereunder, the "LOANS"), with certain financial institutions (collectively,
the "LENDERS") and Citicorp USA, Inc., as administrative agent for the
Lenders (in such capacity, the "ADMINISTRATIVE AGENT").

          B. Under Section 8.2.7 of the Credit Agreement, the Borrower has
agreed not to make any Restricted Payments (as therein defined) unless, INTER
ALIA, the Debt Service Reserve Requirements (as therein defined) is satisfied.

          C. The Debt Service Reserve Requirement may be satisfied by cash,
certain letters of credit, a guarantee by the Guarantor or a combination
thereof.

          D. The Borrower wishes to issue $300 million in aggregate principal
amount of Senior Secured Bonds due 2019 and $530 million in aggregate
principal amount of Senior Secured Bonds due 2026 (collectively, the "BONDS";
the trustee to the holders thereof, the "TRUSTEE"), the proceeds of which
will be used to repay a portion of the Loans, which, in turn, will have the
effect of reducing the amount of the Debt Service Reserve Requirement.

         E. To reflect such reduction in the amount of the Debt Service
Reserve Requirement, the Guarantor has requested, and, upon this Amendment
becoming effective, the Collateral Agent has agreed, that the amount of the
guarantee provided for in the Guarantee be amended in the manner provided for
in this Amendment.

     NOW, THEREFORE, the parties hereto hereby agree as follows:

          1. AMENDMENT OF DEFINITIONS. The definition of the term "Guarantee
Amount" contained in Section 1(b) of the Guarantee is hereby amended by
deleting the current definition in its entirety and substituting in lieu
thereof the following:

<PAGE>

          "GUARANTEE CAP" means three million U.S. Dollars (U.S.$3,000,000).

          2. COUNTERPARTS.  This Amendment may be executed by the parties
hereto in any number of separate counterparts, and all of said counterparts
taken together shall be deemed to constitute one and the same instrument.
Delivery of an executed counterpart of a signature page to this letter by
facsimile shall be effective as delivery of a manually executed counterpart
of this Amendment.

          3. LIMITED EFFECT.  Except as expressly provided herein, all of
the terms and provisions of the Guarantee are and shall remain in full force
and effect.

          4. SEVERABILITY.  Any provision of this Amendment which is
prohibited or unenforceable in any jurisdiction shall, as to such
jurisdiction, be ineffective to the extent of such prohibition or
unenforceability without invalidating the remaining provisions hereof, and
any such prohibition or unenforceability in any jurisdiction shall not
invalidate or render unenforceable such provision in any other jurisdiction.

          5. CONDITIONS TO EFFECTIVENESS.  The amendment provided for herein
shall become effective on the date the Collateral Agent shall have received
counterparts of this Amendment duly executed and delivered by the Guarantor
and consented to by the Administrative Agent and the Trustee.

          6. APPLICABLE LAW.  THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS
OF THE PARTIES HERETO SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN
ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

<PAGE>

          IN WITNESS WHEREOF, the parties hereto have caused this Amendment
to be duly executed and delivered by their respective proper and duly
authorized officers as of the day and year first above written.

                                              EDISON MISSION ENERGY

                                              By: /s/ Steven D. Eisenberg
                                                 ---------------------------
                                                 Name:  Steven D. Eisenberg
                                                 Title: Vice President

                                              UNITED STATES TRUST COMPANY OF
                                              NEW YORK, as Collateral Agent

                                              By: /s/ Christopher J. Grell
                                                 ---------------------------
                                                 Name: Christopher J. Grell
                                                 Title: Assistant Vice President

Acknowledged and Consented to by:

CITICORP USA, INC., as Administrative Agent

By: /s/ Anita J. Brickell
   --------------------------
   Name:  Anita J. Brickell
   Title: Attorney-in-Fact

UNITED STATES TRUST COMPANY OF NEW YORK, as Trustee

By: /s/ Christopher J. Grell
   --------------------------
   Name:  Christopher J. Grell
   Title: Assistant Vice President

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00001-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00001-of-00352.parquet"}]]