April 10, 2001


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

Ladies and Gentlemen:

            We have  acted as  counsel to Indiana  Michigan  Power  Company,  an
Indiana  corporation  (the  "Company"),  in  connection  with  the  Registration
Statement on Form S-3 (the  "Registration  Statement") filed by the Company with
the Securities and Exchange  Commission (the "Commission")  under the Securities
Act of 1933, as amended (the "Act"), relating to Unsecured Notes (the "Unsecured
Notes")  to be  issued  under an  Indenture,  dated as of  October  1, 1998 (the
"Indenture"),  between  the Company  and The Bank of New York,  as Trustee  (the
"Trustee"). The Unsecured Notes may be issued and sold or delivered from time to
time as set forth in the  Registration  Statement,  any amendment  thereto,  the
prospectus   contained  therein  (the   "Prospectus")  and  supplements  to  the
Prospectus  and  pursuant  to Rule 415  under the Act for an  aggregate  initial
offering price not to exceed $550,000,000.

            We have examined the Registration Statement and the Indenture which,
has been filed with the Commission as an exhibit to the Registration  Statement.
We also have  examined the  originals,  or  duplicates or certified or conformed
copies,  of such records,  agreements,  instruments and other documents and have
made such  other and  further  investigations  as we have  deemed  relevant  and
necessary in connection with the opinions  expressed  herein. As to questions of
fact  material  to this  opinion,  we have relied  upon  certificates  of public
officials and of officers and representatives of the Company.

            In  rendering  the  opinions  set forth  below,  we have assumed the
genuineness  of all  signatures,  the legal  capacity  of natural  persons,  the
authenticity  of all documents  submitted to us as originals,  the conformity to
original  documents of all documents  submitted to us as duplicates or certified
or  conformed  copies,  and the  authenticity  of the  originals  of such latter
documents. We also have assumed that: (1) the Indenture is the valid and legally
binding obligation of the Trustee; and (2) the Company is validly existing under
the laws of Indiana.

            We have assumed  further  that (1) the Company has duly  authorized,
executed and delivered the Indenture and (2) execution, delivery and performance
by the Company of Indenture and the Unsecured  Notes do not and will not violate
the laws of  Indiana or any other  applicable  laws  (excepting  the laws of the
State of New York and the Federal laws of the United States).

            Based upon the  foregoing,  and  subject to the  qualifications  and
limitations  stated herein, we are of the opinion that:  assuming (a) the taking
of all  necessary  corporate  action to approve  the  issuance  and terms of the
Unsecured  Notes,  the terms of the offering  thereof and related matters by the
Board of Directors of the Company,  a duly  constituted and acting  committee of
such Board or duly authorized  officers of the Company (such Board of Directors,
committee or authorized  officers  being  referred to herein as the "Board") and
(b) the due execution,  authentication,  issuance and delivery of such Unsecured
Notes,  upon  payment  of  the  consideration  therefore  provided  for  in  the
applicable  definitive  purchase,  underwriting or similar agreement approved by
the Board and otherwise in accordance  with the  provisions of the Indenture and
such agreement,  such Unsecured Notes will constitute  valid and legally binding
obligations of the Company  enforceable  against the Company in accordance  with
their terms,  subject to the effects of (i) bankruptcy,  insolvency,  fraudulent
conveyance,  reorganization,  moratorium  and other  similar laws relating to or
affecting  creditors'  rights  generally,   (ii)  general  equitable  principles
(whether  considered  in a proceeding  in equity or at law) and (iii) an implied
covenant of good faith and fair dealing.

            We are  members  of the Bar of the State of New York,  and we do not
express any opinion herein concerning any law other than the law of the State of
New York and the Federal law of the United States.

            We hereby  consent to the filing of this opinion letter as Exhibit 5
to the  Registration  Statement  and to the use of our name  under  the  caption
"Legal Opinions" in the Prospectus included in the Registration Statement.

                                Very truly yours,

                                    /s/ Simpson Thacher & Bartlett

                                    SIMPSON THACHER & BARTLETT