Exhibit (4)-15
                                                     Commonwealth Edison Company
                                                     Form 10-K File No. 1-1839

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                             SUPPLEMENTAL INDENTURE

                                   __________

                             Dated January 15, 1994

                                   __________



                          COMMONWEALTH EDISON COMPANY

                                       TO

                     CONTINENTAL BANK, NATIONAL ASSOCIATION

                                      AND

                                  M. J. KRUGER

            Trustees under Mortgage Dated July 1, 1923, and Certain
                        Indentures Supplemental Thereto


                                   __________


                           Providing for Issuance of

          FIRST MORTGAGE 5.30% BONDS, POLLUTION CONTROL SERIES 1994A,
          FIRST MORTGAGE 5.70% BONDS, POLLUTION CONTROL SERIES 1994B
                                      AND
          FIRST MORTGAGE 5.85% BONDS, POLLUTION CONTROL SERIES 1994C



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THIS INSTRUMENT PREPARED BY R. R. MIGELY, P.O. BOX 767, CHICAGO, IL 60690, ON
BEHALF OF COMMONWEALTH EDISON COMPANY

 
THIS SUPPLEMENTAL INDENTURE, dated January 15, 1994, between
     COMMONWEALTH EDISON COMPANY, a corporation organized and existing under the
     laws of the State of Illinois (hereinafter called the "Company"), party of
     the first part, and CONTINENTAL BANK, NATIONAL ASSOCIATION, a national
     banking association organized and existing under the laws of the United
     States of America, and M. J. KRUGER, of Chicago, Illinois, as Trustee and
     Co-Trustee, respectively, under the Mortgage of the Company dated July 1,
     1923, as amended and supplemented by Supplemental Indentures dated,
     respectively, August 1, 1944, August 1, 1946, April 1, 1953, April 1, 1966,
     November 1, 1966, December 1, 1966, March 31, 1967, April 1, 1967, February
     1, 1968, July 1, 1968, October 1, 1968, February 28, 1969, May 29, 1970,
     January 1, 1971, June 1, 1971, July 27, 1971, May 31, 1972, June 1, 1973,
     June 15, 1973, October 15, 1973, May 31, 1974, July 1, 1974, March 1, 1975,
     June 13, 1975, May 28, 1976, January 15, 1977, June 1, 1977, June 3, 1977,
     December 1, 1977, May 17, 1978, August 31, 1978, October 15, 1978, June 18,
     1979, June 20, 1980, April 16, 1981, April 30, 1982, April 15, 1983, April
     13, 1984, March 1, 1985, April 15, 1985, April 15, 1986, May 1, 1986,
     August 15, 1986, January 12, 1987, June 30, 1989, February 15, 1990, June
     15, 1990, June 1, 1991, October 1, 1991, October 15, 1991, February 1,
     1992, May 15, 1992, July 15, 1992, September 15, 1992, October 1, 1992,
     February 1, 1993, March 1, 1993, April 1, 1993, April 15, 1993, June 15,
     1993, July 1, 1993 and July 15, 1993, parties of the second part (said
     Trustee being hereinafter called the "Trustee", the Trustee and said Co-
     Trustee being hereinafter together called the "Trustees", and said Mortgage
     dated July 1, 1923, as amended and supplemented by said Supplemental
     Indenture dated August 1, 1944 and subsequent supplemental indentures,
     being hereinafter called the "Mortgage"),

WITNESSETH:

     WHEREAS, the Mortgage provides for the issuance from time to time
thereunder, in series, of bonds of the Company for the purposes and subject to
the limitations therein specified;  and

     WHEREAS, the Company desires, by this Supplemental Indenture, to create
additional series of bonds to be issuable under the Mortgage, such bonds to be
designated "First Mortgage 5.30% Bonds, Pollution Control Series 1994A"
(hereinafter called the "bonds of Series 1994A"), "First Mortgage 5.70% Bonds,
Pollution Control Series 1994B" (hereinafter called the "bonds of Series 1994B")
and "First Mortgage 5.85% Bonds, Pollution Control Series 1994C" (hereinafter
called the "bonds of Series 1994C") and the terms and provisions to be contained
in the bonds of Series 1994A, the bonds of Series 1994B and the bonds of Series
1994C or to be otherwise applicable thereto to be as set forth in this
Supplemental Indenture; and

     WHEREAS, the bonds of Series 1994A and the Trustee's certificate to be
endorsed thereon, the bonds of Series 1994B and the Trustee's certificate to be
endorsed thereon and the bonds of Series 1994C and the Trustee's certificate to
be endorsed thereon shall be substantially in the form of the General Form of
Registered Bond Without Coupons and the


 
form of the General Form of Trustee's Certificate set forth in Section 3.05 of
the Supplemental Indenture dated August 1, 1944, to the Mortgage with such
appropriate insertions, omissions and variations in order to express the
designation, date, maturity date, annual interest rate, record dates for, and
dates of, payment of interest, denominations, terms of redemption and redemption
prices, and other terms and characteristics authorized or permitted by the
Mortgage or not inconsistent therewith; and

     WHEREAS, the Illinois Development Finance Authority (the "Authority")
proposes to issue $66,000,000 aggregate principal amount of its Pollution
Control Revenue Refunding Bonds, Series 1994 (Commonwealth Edison Company
Project) (collectively, the "Revenue Bonds"), pursuant to an Indenture of Trust
dated as of January 15, 1994 (the "Indenture"), under which The First National
Bank of Chicago is trustee (the "Indenture Trustee"), and to use the proceeds
received therefrom to purchase the bonds of Series 1994A, bonds of Series 1994B
and bonds of Series 1994C from the Company, pursuant to a Sale Agreement dated
as of January 15, 1994 (the "Sale Agreement"), between the Company and the
Authority, to assist the Company in refunding certain outstanding obligations
issued to finance a portion of the cost of certain wastewater treatment, air and
water pollution control and sewage and solid waste disposal facilities of the
Company; and the bonds of Series 1994A, bonds of Series 1994B and bonds of
Series 1994C are to be pledged and delivered by the Authority to the Indenture
Trustee to secure the repayment of the Revenue Bonds; and

     WHEREAS, the Company is legally empowered and has been duly authorized by
the necessary corporate action and by orders of the Illinois Commerce Commission
to make, execute and deliver this Supplemental Indenture, and to create, as
additional series of bonds of the Company, the bonds of Series 1994A, bonds of
Series 1994B and bonds of Series 1994C, and all acts and things whatsoever
necessary to make this Supplemental Indenture, when executed and delivered by
the Company and the Trustees, a valid, binding and legal instrument, and to make
the bonds of Series 1994A, bonds of Series 1994B and bonds of Series 1994C, when
authenticated by the Trustee and issued as in the Mortgage and in this
Supplemental Indenture provided, the valid, binding and legal obligations of the
Company, entitled in all respects to the security of the Mortgage, as amended
and supplemented, have been done and performed;

     NOW, THEREFORE, in consideration of the premises and of the sum of one
dollar duly paid by the Trustees to the Company, and for other good and valuable
considerations, the receipt of which is hereby acknowledged, the parties hereto
do hereby agree as follows:

     SECTION 1.  DESIGNATION AND ISSUANCE OF BONDS OF SERIES 1994A, BONDS OF
SERIES 1994B AND BONDS OF SERIES 1994C.  The bonds of Series 1994A shall, as
hereinbefore recited, be designated as the Company's "First Mortgage 5.30%
Bonds, Pollution Control Series 1994A."  The bonds of Series 1994B shall, as
hereinbefore recited, be designated as the Company's "First Mortgage 5.70%
Bonds, Pollution Control Series 1994B."  The bonds of Series 1994C shall, as
hereinbefore recited, be designated as the Company's "First Mortgage 5.85%
Bonds, Pollution Control Series 1994C."  Subject to the provisions of the
Mortgage, the bonds of Series 1994A, bonds of Series 1994B and bonds of Series
1994C shall be issuable without limitation as to the aggregate principal amount
thereof.
 

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     SECTION 2.  FORM, DATE, MATURITY DATE, INTEREST RATE AND INTEREST PAYMENT
DATES OF BONDS OF SERIES 1994A, BONDS OF SERIES 1994B AND BONDS OF SERIES 1994C.
The definitive bonds of Series 1994A, bonds of Series 1994B and bonds of Series
1994C shall be in engraved, lithographed or printed form and shall be registered
bonds without coupons; and such bonds and the Trustee's certificate to be
endorsed thereon shall be substantially in the form hereinbefore recited.  The
bonds of Series 1994A, bonds of Series 1994B and bonds of Series 1994C shall be
dated as provided in Section 3.01 of the Mortgage, as amended by Supplemental
Indenture dated April 1, 1967.  The bonds of Series 1994A shall mature on
January 15, 2004, and shall bear interest at the rate of 5.30% per annum until
the principal thereof shall be paid.  The bonds of Series 1994B shall mature on
January 15, 2009, and shall bear interest at the rate of 5.70% per annum until
the principal thereof shall be paid.  The bonds of Series 1994C shall mature on
January 15, 2014, and shall bear interest at the rate of 5.85% per annum until
the principal thereof shall be paid.  Such interest shall be payable
semiannually on January 15 and July 15 in each year, commencing July 15, 1994.
January 1 and July 1 in each year are hereby established as record dates for the
payment of interest payable on the next succeeding interest payment dates,
respectively.  The interest on each bond of Series 1994A, each bond of Series
1994B and each bond of Series 1994C so payable on any interest payment date
shall, subject to the exceptions provided in Section 3.01 of the Mortgage, as
amended by said Supplemental Indenture dated April 1, 1967, be paid to the
person in whose name such bond is registered at the close of business on January
1 and July 1, as the case may be, next preceding such interest payment date.

     SECTION 3.  EXECUTION OF BONDS OF SERIES 1994A, BONDS OF SERIES 1994B AND
BONDS OF SERIES 1994C.  The bonds of Series 1994A, bonds of Series 1994B and
bonds of Series 1994C shall be executed on behalf of the Company by its
President or one of its Vice Presidents, manually or by facsimile signature, and
shall have its corporate seal affixed thereto or a facsimile of such seal
imprinted thereon, attested by its Secretary or one of its Assistant
Secretaries, manually or by facsimile signature, all as may be provided by
resolution of the Board of Directors of the Company.  In case any officer or
officers whose signature or signatures, manual or facsimile, shall appear upon
any bond of Series 1994A, any bond of Series 1994B or any bond of Series 1994C
shall cease to be such officer or officers before such bond shall have been
actually authenticated and delivered, such bond nevertheless may be issued,
authenticated and delivered with the same force and effect as though the person
or persons whose signature or signatures, manual or facsimile, appear thereon
had not ceased to be such officer or officers of the Company.

     SECTION 4.  MEDIUM AND PLACES OF PAYMENT OF PRINCIPAL OF AND INTEREST ON
BONDS OF SERIES 1994A, BONDS OF SERIES 1994B AND BONDS OF SERIES 1994C;
TRANSFERABILITY AND EXCHANGEABILITY.  Both the principal of and interest on the
bonds of Series 1994A, bonds of Series 1994B and bonds of Series 1994C shall be
payable in any coin or currency of the United States of America which at the
time of payment is legal tender for the payment of public and private debts, and
both such principal and interest shall be payable at the office or agency of the
Company in the City of Chicago, State of Illinois, or, at the option of the
registered owner, at the office or agency of the Company in the Borough of
Manhattan, The City of New York, State of New York. There shall be credited
against amounts due from time to time on the


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bonds of Series 1994A, bonds of Series 1994B and bonds of Series 1994C any
amounts then on deposit in the Bond Fund created by Section 402 of the
Indenture.  Bonds of Series 1994A, bonds of Series 1994B and bonds of Series
1994C shall not be transferable except to the Authority, the Indenture Trustee
or any successor trustee under the Indenture.  Bonds of Series 1994A, bonds of
Series 1994B and bonds of Series 1994C shall be exchangeable for other bonds of
authorized denominations, in the manner provided in Sections 3.09 and 3.10 of
the Mortgage, at said office or agency.  No charge shall be made by the Company
to the registered owner of any bond of Series 1994A, any bond of Series 1994B or
any bond of Series 1994C for the transfer of such bond or for the exchange
thereof for bonds of other authorized denominations, except, in the case of
transfer, a charge sufficient to reimburse the Company for any stamp or other
tax or governmental charge required to be paid by the Company or the Trustee.

     SECTION 5.  DENOMINATIONS AND NUMBERING OF BONDS OF SERIES 1994A, BONDS OF
SERIES 1994B AND BONDS OF SERIES 1994C.  The bonds of Series 1994A, bonds of
Series 1994B and bonds of Series 1994C shall be issued in the denomination of
$5,000 and in such multiples of $5,000 as shall from time to time hereafter be
determined and authorized by the Board of Directors of the Company or by any
officer or officers of the Company authorized to make such determination, the
authorization of the denomination of any bond of Series 1994A, any bond of
Series 1994B or any bond of Series 1994C to be conclusively evidenced by the
execution thereof on behalf of the Company.  Bonds of Series 1994A shall be
numbered R-1 and consecutively upwards, bonds of Series 1994B shall be numbered
R-1 and consecutively upwards and bonds of Series 1994C shall be numbered R-1
and consecutively upwards.

     SECTION 6.  TEMPORARY BONDS OF SERIES 1994A, BONDS OF SERIES 1994B AND
BONDS OF SERIES 1994C.  Until definitive bonds of Series 1994A, bonds of Series
1994B or bonds of Series 1994C are ready for delivery, there may be
authenticated and issued in lieu of any thereof and subject to all of the
provisions, limitations and conditions set forth in Section 3.11 of the
Mortgage, temporary registered bonds without coupons of bonds of Series 1994A,
bonds of Series 1994B or bonds of Series 1994C.

     SECTION 7.  EXTRAORDINARY OPTIONAL REDEMPTION OF BONDS OF SERIES 1994A,
BONDS OF SERIES 1994B AND BONDS OF SERIES 1994C.  Upon the notice and in the
manner provided in Section 301 of the Indenture, the bonds of Series 1994A,
bonds of Series 1994B and bonds of Series 1994C may be redeemed prior to
maturity at the option of the Company, in whole but not in part, at any time at
100% of the principal amount thereof plus accrued interest to the redemption
date, within 180 days after the occurrence of any change in the Constitution of
the State of Illinois or the Constitution of the United States of America or any
legislative or administrative action (whether local, state or federal) or any
final decree, judgment or order of any court or administrative body (whether
local, state or federal) which results in the Sale Agreement, the bonds of
Series 1994A, bonds of Series 1994B or bonds of Series 1994C becoming void or
unenforceable or impossible of performance in accordance with the intent and
purpose of the parties as expressed in the Sale Agreement, the bonds of Series
1994A, bonds of Series 1994B or bonds of Series 1994C, as the case may be.


                                      -4-


 
     SECTION 8.  EXTRAORDINARY MANDATORY REDEMPTION OF BONDS OF SERIES 1994A,
BONDS OF SERIES 1994B AND BONDS OF SERIES 1994C.  Upon the notice and in the
manner provided in Section 301 of the Indenture, the bonds of Series 1994A,
bonds of Series 1994B and bonds of Series 1994C shall be redeemed by the Company
in whole, or as hereinafter provided in part, at 100% of the principal amount
thereof plus accrued interest to the redemption date, in the event of a final
determination by the Internal Revenue Service or by a court of competent
jurisdiction that, as a result of a failure by the Company to observe any
covenant, agreement, representation or warranty in the Sale Agreement or the Tax
Exemption Certificate and Agreement dated January 25, 1994, between the Company
and the Authority, the interest payable on the Revenue Bonds is includable in
the gross income for federal income tax purposes of the owners thereof (other
than an owner who is a "substantial user" of the Project (as defined in the
Indenture) or a "related person" within the meaning of Section 103(b)(13) of the
Internal Revenue Code of 1954, as amended (the "Code")).  Such a determination
will not result from the inclusion of interest on any Revenue Bond in the
computation of minimum or indirect taxes.  Any such determination shall not be
considered final for this purpose unless the Company has been given written
notice of any proceedings which might result in such determination and has been
afforded the opportunity to participate in any such proceedings (as a party or
otherwise) to the extent the Company deems sufficient, either directly or in the
name of any owner of a Revenue Bond, and until the conclusion of any appellate
review, if sought.  Any such redemption shall occur within 180 days from the
date of such final determination.  The bonds of Series 1994A, bonds of Series
1994B and bonds of Series 1994C shall be redeemed in whole upon any such final
determination unless, in the opinion of Bond Counsel (as defined in the
Indenture), the redemption of a portion of the outstanding Revenue Bonds would
have the result that interest payable on the Revenue Bonds remaining outstanding
after such redemption would not be includable in the gross income for federal
income tax purposes of any owner of such Revenue Bonds (other than an owner who
is a "substantial user" of the Project or a "related person" within the meaning
of Section 103(b)(13) of the Code), in which event bonds of Series 1994A, bonds
of Series 1994B and bonds of Series 1994C shall be redeemed in an amount equal
to the amount of Revenue Bonds required to be so redeemed.  If any holder of
Revenue Bonds refuses to permit the Company to participate in any such
proceedings (as a party or otherwise) to the extent the Company deems sufficient
or if any  holder of Revenue Bonds fails to notify the Company of the pendency
of any such proceedings, the bonds of Series 1994A, bonds of Series 1994B and
bonds of Series 1994C shall not, in the event of an adverse final determination,
be subject to the mandatory redemption provisions of this Section.

     SECTION 9.  DEFAULT MANDATORY REDEMPTION.  The bonds of Series 1994A, bonds
of Series 1994B and bonds of Series 1994C shall be redeemed promptly, without
notice, by the Company in whole at 100% of the principal amount thereof plus
accrued interest to the date of redemption following receipt by the Trustee of
written notice from the Indenture Trustee stating that the principal of the
Revenue Bonds has been declared to be immediately due and payable as a result of
an event of default under the Indenture.


                                      -5-


 
     SECTION 10.  MISCELLANEOUS.  The terms and conditions of this Supplemental
Indenture shall be deemed to be a part of the terms and conditions of the
Mortgage for any and all purposes.  The Mortgage, as supplemented by said
indentures supplemental thereto dated subsequent to August 1, 1944 and referred
to in the first paragraph of this Supplemental Indenture, and as further
supplemented by this Supplemental Indenture, is in all respects hereby ratified
and confirmed.

     This Supplemental Indenture shall bind and, subject to the provisions of
Article XIV of the Mortgage, inure to the benefit of the respective successors
and assigns of the parties hereto.

     Although this Supplemental Indenture is dated January 15, 1994, it shall be
effective only from and after the actual time of its execution and delivery by
the Company and the Trustees on the date indicated by their respective
acknowledgments hereto annexed.

     This Supplemental Indenture may be simultaneously executed in any number of
counterparts, and all such counterparts executed and delivered, each as an
original, shall constitute but one and the same instrument.


                                      -6-

 
     IN WITNESS WHEREOF, Commonwealth Edison Company has caused this
Supplemental Indenture to be executed in its name by one of its Vice Presidents,
and its seal to be hereunto affixed and attested by its Secretary, and
Continental Bank, National Association, as Trustee under the Mortgage, has
caused this Supplemental Indenture to be executed in its name by one of its Vice
Presidents, and its seal to be hereunto affixed and attested by one of its Trust
Officers, and M. J. Kruger, as Co-Trustee under the Mortgage, has hereunto
affixed his signature and seal, all as of the day and year first above written.

                                                COMMONWEALTH EDISON COMPANY


                                                By       /s/ J. C. Bukovski
                                                         J. C. Bukovski
                                                          Vice President

                                                                (SEAL)
ATTEST:

     /s/ David A. Scholz
     David A. Scholz
        Secretary

                                                CONTINENTAL BANK, NATIONAL
                                                  ASSOCIATION


                                                By     /s/ Joanne M. Murphy
                                                       Joanne M. Murphy
                                                        Vice President

                                                                (SEAL)
ATTEST:

     /s/ K L Clark
     K. L. Clark
       Trust Officer

                                                     /s/ M J Kruger
                                                     M. J. KRUGER

                                                                (SEAL)


                                      -7-

 
STATE OF ILLINOIS  )
                   ) SS.
COUNTY OF COOK     )



     I,   JOHN R. DIETZEL, a Notary Public in and for said County, in the State
aforesaid, DO HEREBY CERTIFY that J. C. BUKOVSKI, a Vice President of
Commonwealth Edison Company, an Illinois corporation, one of the parties
described in and which executed the foregoing instrument, and DAVID A. SCHOLZ,
the Secretary of said corporation, who are both personally known to me to be the
same persons whose names are subscribed to the foregoing instrument as such Vice
President and Secretary, respectively, and who are both personally known to me
to be a Vice President and the Secretary, respectively, of said corporation,
appeared before me this day in person and severally acknowledged that they
signed, sealed, executed and delivered said instrument as their free and
voluntary act as such Vice President and Secretary, respectively, of said
corporation, and as the free and voluntary act of said corporation, for the uses
and purposes therein set forth.

     GIVEN under my hand and notarial seal this 17th day of January, A.D. 1994.



                                                        /s/ John R. Dietzel
                                                        John R. Dietzel
                                                        Notary Public

(SEAL)


My Commission expires March 10, 1997


                                      -8-

 
STATE OF ILLINOIS  )
                   ) SS.
COUNTY OF COOK     )


     I,  S. RHODEN,   a Notary Public in and for said County, in the State
aforesaid, DO HEREBY CERTIFY that JOANNE M. MURPHY, a Vice President of
Continental Bank, National Association, a national banking association, one of
the parties described in and which executed the foregoing instrument, and K. L.
CLARK, a Trust Officer of said banking association, who are both personally
known to me to be the same persons whose names are subscribed to the foregoing
instrument as such Vice President and Trust Officer, respectively, and who are
both personally known to me to be a Vice President and a Trust Officer,
respectively, of said banking association, appeared before me this day in person
and severally acknowledged that they signed, sealed, executed and delivered said
instrument as their free and voluntary act as such Vice President and Trust
Officer, respectively, of said banking association, and as the free and
voluntary act of said banking association, for the uses and purposes therein set
forth.

     GIVEN under my hand and notarial seal this 17th day of January, A.D. 1994.



                                                         /s/ S. Rhoden
                                                         S. Rhoden
                                                         Notary Public

(SEAL)


My Commission expires June 28, 1997.


                                      -9-

 
STATE OF ILLINOIS  )
                   ) SS.
COUNTY OF COOK     )



     I,   S. RHODEN,   a Notary Public in and for said County, in the State
aforesaid, DO HEREBY CERTIFY that M. J. KRUGER, one of the parties described in
and which executed the foregoing instrument, who is personally known to me to be
the same person whose name is subscribed to the foregoing instrument, appeared
before me this day in person and acknowledged that he signed, sealed, executed
and delivered said instrument as his free and voluntary act for the uses and
purposes therein set forth.

     GIVEN under my hand and notarial seal this 17th day of January, A.D. 1994.



                                                         /s/ S. Rhoden
                                                         S. Rhoden
                                                         Notary Public

(SEAL)


My Commission expires June 28, 1997.



                                       COMMONWEALTH EDISON COMPANY
                                       REAL ESTATE DEPT.
                                       P. O. BOX 767
                                       CHICAGO, ILLINOIS  60690


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