Exhibit 5
                          October 2, 1998


Indiana Michigan Power Company
One Summit Square
Fort Wayne, Indiana  46801

Dear Sirs:

      With respect to the Registration Statement on Form S-3 of Indiana Michigan
Power Company (the  "Company")  relating to the issuance and sale by the Company
in one or more  transactions  from  time to time  of its  Unsecured  Notes  (the
"Unsecured Notes") under an Indenture to be entered into between the Company and
The Bank of New York,  as Trustee  (the  "Indenture"),  we wish to advise you as
follows.

      We are of the Opinion that, when the steps mentioned in the next paragraph
below have been taken,  the  Unsecured  Notes will be valid and legally  binding
obligations of the Company,  subject to the effects of  bankruptcy,  insolvency,
fraudulent  conveyance,  reorganization,   moratorium  and  other  similar  laws
relating  to  or  affecting  creditors'  rights  generally,   general  equitable
principles  (whether  considered  in a  proceeding  in  equity or at law) and an
implied covenant of good faith and fair dealing.

      The  steps  to be  taken  which  are  referred  to in the  next  preceding
paragraph consist of the following:

      (1)Appropriate  definitive action by the Board of Directors of the Company
         with   respect  to  the  proposed   transactions   set  forth  in  said
         Registration Statement;

      (2)Appropriate  action  by  and  before  the  Indiana  Utility  Regulatory
         Commission  in respect of the proposed  transactions  set forth in said
         Registration Statement;

      (3)Compliance  with the Securities  Act of 1933, as amended,  and with the
         Trust Indenture Act of 1939, as amended;

      (4) Execution and delivery of the Indenture; and

      (5)Issuance and sale of the  Unsecured  Notes by the Company in accordance
         with the Indenture and the  governmental  and corporate  authorizations
         aforesaid.

    Insofar as this opinion  relates to matters  governed by laws other than the
laws of the State of New York and the  Federal  law of the United  States,  this
firm has consulted, and may consult further, with counsel in which this firm has
confidence  and will rely, as to such  matters,  upon such opinions or advice of
such  counsel  which will be  delivered to this firm prior to the closing of the
sale of the Unsecured Notes.

      We  consent  to  the  filing  of  this  opinion  as  an  exhibit  to  said
Registration  Statement  and to the use of our  name  and the  inclusion  of the
statements in regard to us set forth in said  Registration  Statement  under the
caption "Legal Opinions".

                          Very truly yours,


                          /s/ Simpson Thacher & Bartlett

                          SIMPSON THACHER & BARTLETT