EXHIBIT 10.3

                         UNILATERAL BORROWING AGREEMENT


     This UNILATERAL BORROWING AGREEMENT  ("Agreement") made and entered into on
the 30th day of September, 2004, among Ameren Corporation ("Ameren"), a Missouri
corporation  and a registered  holding  company under the Public Utility Holding
Company Act of 1935,  as amended,  Illinois  Power  Company,  doing  business as
AmerenIP  ("AmerenIP"),  an Illinois  corporation  and a utility  subsidiary  of
Ameren and Ameren  Services  Company,  a Missouri  corporation  and a subsidiary
service company of Ameren ("Ameren  Services") (each a "Party" and collectively,
the "Parties").

     WHEREAS,  AmerenIP is expected to need from time to time to borrow funds on
a short-term basis;

     WHEREAS,  Ameren and  AmerenIP  desire to enter into an  agreement  whereby
AmerenIP will be able to make such  short-term  borrowings  directly from Ameren
from time to time;

     WHEREAS,  the Parties  contemplate that AmerenIP will become a party to the
Ameren  Corporation  Utility  Money Pool  Agreement,  dated March 25,  1999,  as
amended ("Utility Money Pool"); and

     WHEREAS,  this  Agreement  is subject  to and  designed  to comply  with 83
Illinois Administrative Code Part 340 (the "ICC Money Pool Rules").

     NOW THEREFORE,  in consideration  of the premises,  and the mutual promises
set forth herein, the Parties hereto agree as follows:

     ARTICLE I: BORROWINGS BY AMERENIP

     Section 1.1 Rights to Borrow.  Subject to the  provisions of Section 1.3(b)
of this  Agreement,  Ameren  agrees to meet any  short-term  borrowing  needs of
AmerenIP up to an aggregate amount  outstanding at any time of $500 million (the
"Available  Limit").  There shall be deducted from the Available Limit any other
outstanding  short-term debt obligations of AmerenIP including,  but not limited
to, amounts owing under the Utility Money Pool. AmerenIP shall have the right to
make short-term borrowings under this Agreement,  subject to the availability of
funds and the  limitations and conditions set forth herein and in the applicable
orders of the  Securities  and  Exchange  Commission  ("SEC")  and the  Illinois
Commerce  Commission  ("ICC")  and  limitations  of the ICC  Money  Pool  Rules.
AmerenIP  may request  loans under this  Agreement  from time to time during the
period  from the date  hereof  until this  Agreement  is  terminated  by written
agreement of the Parties upon not less than 10 days notice;  provided,  however,
that the aggregate amount of all loans requested by AmerenIP hereunder shall not
exceed the  applicable  borrowing  limits set forth in applicable  orders of the
SEC, the ICC, and other  relevant  regulatory  authorities,  resolutions of such
Party's  shareholders and Board of Directors,




such Party's governing  corporate  documents,  and agreements  binding upon such
Party. Ameren may not borrow under this Agreement from AmerenIP.

     Section 1.2 Source of Funds.  (a) Funds will be made available by Ameren to
AmerenIP through this Agreement from the following sources: (i) surplus funds in
the treasury of Ameren ("Internal Funds") and (ii) proceeds from bank borrowings
and the sale of commercial paper by Ameren ("External  Funds"),  in each case to
the extent  permitted by applicable  laws and regulatory  orders.  Funds will be
made available from such sources in such order as the Parties may determine will
result in a lower cost of borrowing to the Parties  consistent  with  AmerenIP's
borrowing needs and financial standing of Ameren.

     (b) On any day when more than one fund  source  (e.g.,  Internal  Funds and
External Funds),  with different rates of interest,  is used to fund loans under
this Agreement,  AmerenIP will borrow pro rata from each fund source in the same
proportion  that the amount of funds  provided by that fund source  bears to the
total amount of short-term funds available hereunder.

     Section 1.3  Authorization.  (a) Each loan shall be  authorized by Ameren's
Treasurer, or by a designee thereof.

     (b) All borrowings  under this Agreement  shall be authorized by AmerenIP's
Treasurer, or by a designee thereof.  AmerenIP shall not be required to effect a
borrowing  under this Agreement if it determines  that it can (and is authorized
to) effect  such  borrowing  at lower cost  through  the  Utility  Money Pool or
directly  from  banks  or  through  the sale of its own  commercial  paper in an
existing commercial paper program.

     Section 1.4 Interest. Interest shall accrue monthly on the unpaid principal
amount of loans made under this  Agreement from the date of such loan until such
principal amount shall be paid in full.

     (a) If only Internal Funds comprise the funds loaned to AmerenIP under this
Agreement, the interest rate applicable to loans of such Internal Funds shall be
the CD  yield  equivalent  of the  30-day  Federal  Reserve  "AA"  Non-Financial
commercial  paper  composite rate (or, if no such rate is  established  for that
day, then the  applicable  rate shall be the rate for the next preceding day for
which such rate was established).

     (b) If only External Funds comprise the funds loaned to AmerenIP under this
Agreement, the interest rate applicable to loans of such External Funds shall be
equal to Ameren's cost for such External  Funds.  The rate of interest shall not
exceed the rate permitted by Section 340.30 (c) of the ICC Money Pool Rules.

     (c) In cases where both  Internal  Funds and  External  Funds  comprise the
funds loaned to AmerenIP under this Agreement,  the rate applicable to all loans
comprised  of such  "blended"  funds  shall be a  composite  rate,  equal to the
weighted  average of the (i)

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cost of all Internal Funds (as determined  pursuant to Section 1.4(a) above) and
(ii) the cost of all such  External  Funds (as  determined  pursuant  to Section
1.4(b) above); provided, that in circumstances where Internal Funds and External
Funds  are  available  for  loans  under  this  Agreement,  loans  may  be  made
exclusively from Internal Funds or External Funds, rather than from a "blend" of
such funds, to the extent it is expected that such loans would result in a lower
cost of borrowing.

     Section 1.5 Certain Costs.  The cost of  compensating  balances and/or fees
paid to banks to maintain  credit  lines shall  initially  be paid by Ameren.  A
portion of such costs shall be  retroactively  allocated every month to AmerenIP
as a borrower  of External  Funds  under this  Agreement  in  proportion  to its
respective  daily  outstanding  borrowings of such External Funds  calculated as
required for "issuance costs" under the ICC Money Pool Rules.

     Section 1.6 Repayment.  AmerenIP shall repay the principal  amount of loans
made under this Agreement, together with all interest accrued thereon, on demand
and in any event  within one year of the date on which  such loan was made.  All
loans made by AmerenIP  under this  Agreement may be prepaid at any time without
premium or penalty.

     Section  1.7 Form of Loans to  AmerenIP.  Loans made by Ameren to  AmerenIP
under this Agreement will be made pursuant to open-account  advances,  repayable
upon  demand  and in any  event not  later  than one year  after the date of the
advance;  provided,  that Ameren  shall at all times be entitled to receive upon
demand one or more promissory notes evidencing any and all loans made by it. Any
such note shall:  (a) be substantially in the form attached as Exhibit A hereto,
(b) be dated as of the date of the initial borrowing, (c) mature on demand or on
a date agreed by the Parties to the transaction, but in any event not later than
one year after the date of the  applicable  borrowing,  and (d) be  repayable in
whole at any time or in part from time to time, without premium or penalty.

     ARTICLE II: OPERATION OF THIS UNILATERAL BORROWING
                 AGREEMENT

     Section  2.1  Operation.  Operation  of this  Agreement,  including  record
keeping and coordination of loans,  will be handled by Ameren Services under the
authority of the appropriate  officers of the Parties.  Ameren Services shall be
responsible for the  determination of all applicable  interest rates and charges
to be applied to advances  outstanding  at any time  hereunder,  shall  maintain
records  of all  advances,  interest  charges  and  accruals  and  interest  and
principal  payments for purposes  hereof,  and shall  prepare  periodic  reports
thereof for the Parties.  Ameren  Services will  administer this Agreement on an
"at cost"  basis.  Separate  records  shall be kept by Ameren  Services for this
Agreement and any other  intercompany  borrowing  arrangements  administered  by
Ameren Services.  Ameren Services will keep necessary  records and shall prepare
and file on behalf of  AmerenIP  the  reports  and  information  required  to be
submitted to the Illinois  Commerce  Commission  under Section 340.60 of the ICC
Money Pool Rules.


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     Section 2.2 Event of Default. If AmerenIP shall generally not pay its debts
as such debts  become due, or shall  admit in writing its  inability  to pay its
debts  generally,  or  shall  make a  general  assignment  for  the  benefit  of
creditors,  or any proceeding shall be instituted by or against AmerenIP seeking
to  adjudicate  it a bankrupt or  insolvent,  then Ameren may declare the unpaid
principal  amount of any loans to  AmerenIP,  and all  interest  thereon,  to be
forthwith  due and payable and all such amounts shall  forthwith  become due and
payable.

     ARTICLE III: MISCELLANEOUS

     Section 3.1  Amendments.  No amendment to this  Agreement  shall be adopted
except in a writing executed by the Parties.

     Section 3.2 Legal Responsibility. Nothing herein contained shall render any
Party liable for the obligations of any other Party hereunder.

     Section  3.3  Governing  Law.  This  Agreement  shall be  governed  by, and
construed in accordance with, the laws of the State of Missouri.

     IN  WITNESS  WHEREOF,  the  undersigned  companies  have duly  caused  this
document  to be  signed  on  their  behalf  on the  date  written  above  by the
undersigned thereunto duly authorized.

AMEREN CORPORATION


By      /s/ Jerre E. Birdsong
      -------------------------------
Name:   Jerre E. Birdsong
Title:  Vice President and Treasurer


ILLINOIS POWER COMPANY


By      /s/ Jerre E. Birdsong
      -------------------------------
Name:   Jerre E. Birdsong
Title:  Vice President and Treasurer


AMEREN SERVICES COMPANY


By      /s/ Jerre E. Birdsong
      -------------------------------
Name:   Jerre E. Birdsong
Title:  Vice President and Treasurer


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                                                                      EXHIBIT A

                   FORM OF UNILATERAL BORROWING AGREEMENT NOTE

$ (See attached schedule for principal amount                    [Date]
         outstanding at any time.)

     FOR VALUE RECEIVED, the undersigned, Illinois Power Company d/b/a AmerenIP,
an Illinois corporation (the "Company"),  hereby unconditionally promises to pay
to the order of Ameren  Corporation  (the  "Lender"),  on  demand,  or on a date
agreed to by the Company and the Lender (but in any case not later than one year
after  the  date  of  the  applicable  borrowing),  at  the  offices  of  Ameren
Corporation,  in lawful money of the United States of America and in immediately
available  funds,  the aggregate  unpaid principal amount of all loans (that are
posted on the schedule annexed hereto and made a Part hereof) made by the Lender
to the Company under the Unilateral Borrowing  Agreement,  dated as of ________,
(the  "Agreement")  between  Lender and the Company.  Borrowings  by the Company
under the Agreement are in accordance with approvals in effect from time to time
of the  Securities  and Exchange  Commission  under the Public  Utility  Holding
Company  Act  of  1935,  as  amended  and  approvals  of the  Illinois  Commerce
Commission.

     The  Company  further  agrees to pay in like money at such  office  accrued
interest on the unpaid  principal  amount hereof from time to time from the date
of the  applicable  borrowing  at the  rate as  determined  by  Ameren  Services
Company, in its capacity as a administrator of the Agreement, in accordance with
the terms and provisions of the Agreement.  Interest shall be payable monthly in
arrears and upon payment (including  prepayment) in full of the unpaid principal
amount hereof.

     This Note shall be governed by, and construed and interpreted in accordance
with, the Laws of the State of Missouri.

     IN WITNESS WHEREOF,  the undersigned,  pursuant to due  authorization,  has
caused  this  Note to be  executed  in its  name and on its  behalf  by its duly
authorized officer.

                                          Illinois Power Company
                                          d/b/a AmerenIP

                                          By: _________________________
                                              Name:
                                              Title: