EXHIBIT 99.3

                            MIDWEST GENERATION, LLC
                           OFFER FOR ALL OUTSTANDING
           $333,500,000 8.30% SERIES A PASS-THROUGH CERTIFICATES AND
             $813,500,000 8.56% SERIES B PASS-THROUGH CERTIFICATES
                                IN EXCHANGE FOR
    IDENTICAL PRINCIPAL AMOUNTS OF 8.30% SERIES A PASS-THROUGH CERTIFICATES
                  AND 8.56% SERIES B PASS-THROUGH CERTIFICATES
                        WHICH HAVE BEEN REGISTERED UNDER
                          THE SECURITIES ACT OF 1933,
                                   AS AMENDED

TO OUR CLIENTS:

    Enclosed for your consideration is a Prospectus, dated            , 2001
(the "Prospectus"), and the related Letter of Transmittal (the "Letter of
Transmittal"), relating to the offer (the "Exchange Offer") of Midwest
Generation, LLC (the "Company") to exchange up to $333,500,000 aggregate
principal amount of new 8.30% Series A Pass-Through Certificates and up to
$813,500,000 aggregate principal amount of new 8.56% Series B Pass-Through
Certificates, which have been registered under the Securities Act of 1933, as
amended (the "Exchange Certificates"), for an equal principal amount of its
outstanding 8.30% Series A Pass-Through Certificates and 8.56% Series B
Pass-Through Certificates (the "Original Certificates"), upon the terms and
subject to the conditions described in the Prospectus and the Letter of
Transmittal. The Exchange Offer is being made in order to satisfy certain
obligations of the Company contained in the Registration Rights Agreement dated
August 17, 2000, by and among Edison Mission Energy, the Company and Credit
Suisse First Boston Corporation and Lehman Brothers Inc., as representatives of
the initial purchasers referred to therein.

    This material is being forwarded to you as the beneficial owner of the
Original Certificates held by us for your account but not registered in your
name. A TENDER OF SUCH ORIGINAL CERTIFICATES MAY ONLY BE MADE BY US AS THE
HOLDER OF RECORD AND PURSUANT TO YOUR INSTRUCTIONS.

    Accordingly, we request instructions as to whether you wish us to tender on
your behalf the Original Certificates held by us for your account, pursuant to
the terms and conditions set forth in the enclosed Prospectus and Letter of
Transmittal.

    Your instructions should be forwarded to us as promptly as possible in order
to permit us to tender the Original Certificates on your behalf in accordance
with the provisions of the Exchange Offer. The Exchange Offer will expire at
5:00 P.M., New York City time, on            , 2001, unless extended by the
Company. Any Original Certificates tendered pursuant to the Exchange Offer may
be withdrawn at any time before the Expiration Date.

    Your attention is directed to the following:

        1.  The Exchange Offer is for any and all Original Certificates.

        2.  The Exchange Offer is subject to certain conditions set forth in the
    Prospectus in the section captioned "The Exchange Offer--Conditions to the
    Exchange Offer."

        3.  Any transfer taxes incident to the transfer of Original Certificates
    from the holder to the Company will be paid by the Company, except as
    otherwise provided in the Instructions in the Letter of Transmittal.

        4.  The Exchange Offer expires at 5:00 P.M., New York City time, on
               , 2001, unless extended by the Company.

    If you wish to have us tender your Original Certificates, please so instruct
us by completing, executing and returning to us the instruction form on the back
of this letter. THE LETTER OF TRANSMITTAL IS FURNISHED TO YOU FOR INFORMATION
ONLY AND MAY NOT BE USED DIRECTLY BY YOU TO TENDER ORIGINAL CERTIFICATES.

                          INSTRUCTIONS WITH RESPECT TO
                               THE EXCHANGE OFFER

    The undersigned acknowledge(s) receipt of your letter and the enclosed
material referred to therein relating to the Exchange Offer made by Midwest
Generation, LLC with respect to its Original Certificates.

    This will instruct you to tender the Original Certificates held by you for
the account of the undersigned, upon and subject to the terms and conditions set
forth in the Prospectus and the related Letter of Transmittal.

    The undersigned expressly agrees to be bound by the enclosed Letter of
Transmittal and that such Letter of Transmittal may be enforced against the
undersigned.

    Please tender the Original Certificates held by you for my account as
indicated below:

       8.30% Series A Pass-Through Certificates $________ (Aggregate Principal
       Amount of Original Certificates)

       8.56% Series B Pass-Through Certificates $________ (Aggregate Principal
       Amount of Original Certificates)

       / / Please do not tender any Original Certificates held by you for my
       account.

       Dated: ___________, 2001

Signature(s): __________________________________________________________________

Print Name(s) here: ____________________________________________________________

(Print Address(es)): ___________________________________________________________

(Area Code and Telephone Number(s)): ___________________________________________

(Tax Identification or Social Security Number(s)): _____________________________

    None of the Original Certificates held by us for your account will be
tendered unless we receive written instructions from you to do so. Unless a
specific contrary instruction is given in the space provided, your signature(s)
hereon shall constitute an instruction to us to tender all the Original
Certificates held by us for your account.

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