AMENDMENT ONE TO REVOLVING CREDIT AGREEMENT

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Exhibit 10.1

AMENDMENT ONE TO REVOLVING CREDIT AGREEMENT

        THIS AMENDMENT ONE TO REVOLVING CREDIT AGREEMENT (this " Amendment ") dated as of August 30, 2005, by and between EDISON MISSION MARKETING & TRADING, INC., a California corporation, as borrower (" Borrower "), and MIDWEST GENERATION, LLC, a Delaware limited liability company, as lender (" Lender ").

        WHEREAS, the Borrower and the Lender entered into a Revolving Credit Agreement dated as of April 27, 2004 (the " Credit Agreement ");

        WHEREAS, the Borrower has requested that the Lenders increase the amount of loans permitted to be made under the Credit Agreement; and

        WHEREAS, Lender is willing to agree to the amendments provided for in this Amendment on the terms and conditions hereof.

        ACCORDINGLY, the parties hereto agree as follows:

        Section 1.     Definitions .    Except as otherwise defined in this Amendment, terms defined in the Credit Agreement are used herein (and in the introductions and recitals hereto) as defined therein.

        Section 2.     Amendment to the Credit Agreement .    The Credit Agreement shall hereby be amended as follows:

        (a)   Section 2.1 of the Credit Agreement is hereby amended and restated in its entirety as follows:

Borrowings/Letters of Credit. From time to time on any day occurring prior to the Termination Date, Lender shall make loans to Borrower (each a " Revolving Loan "), and/or cause to be issued letters of credit on behalf of Borrower (each a " Letter of Credit ") in the amounts requested in writing by a Borrower's Representative; provided that (i) the aggregate amount of Revolving Loans and Letters of Credit outstanding shall not at any time exceed $500,000,000 (the " Revolver Commitment ") and (ii) Lender shall not be required to make any such loan or cause the issuance of such letters of credit unless doing so would constitute the provision of Permitted Marketing Support by Lender.    Borrower may from time to time borrow, prepay, in whole or in part, and reborrow Revolving Loans and/or request the cancellation or reissuance of Letters of Credit. Simultaneously herewith, borrower shall execute a promissory note for Revolving Loans in form and substance substantially similar to Exhibit A hereto or otherwise in form and substance as is agreed by the parties hereto (the " Revolver Note "), in either case in the principal amount of the Revolver Commitment.

        (b)   The form of Note attached as Exhibit A to the Credit Agreement is hereby amended and restated in its entirety as set forth in Exhibit A to this Amendment. Borrower shall execute and deliver to Lender a new promissory note in the form of Exhibit A to this Amendment (the "Replacement Note"), whereupon Lender shall (a) update the grid of the Replacement Note to reflect all Borrowings then in place under the Credit Agreement; and (b) cancel and return to Borrower the Note previously executed in connection with the Credit Agreement.

        Section 3.     Miscellaneous .    Except as expressly amende