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                                        March 30, 2001

Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, D.C.  20549

          RE:  NISOURCE INC.
               FILE NO. 70-9551

     On behalf of NiSource Inc. ("NiSource"), and Columbia Energy Group ("CEG"),
we are submitting, under the Public Utility Holding Company Act of 1935 ("Act"),
in the above file this letter of notification pursuant to Rule 24 (which may
also serve as a post-effective amendment to the Application-Declaration on Form
U-1, as previously amended ("U-1")).

     The order of the Securities and Exchange Commission ("Commission"), dated
October 30, 2000, with respect to the U-1 ("Order") (Holding Co. Act Release No.
27263) required that NiSource advise the Commission no later than March 31, 2001
of its arrangements for a "subsidiary service company" and the service agreement
to be used by that service company in providing services to its affiliated
companies in the NiSource System. In accordance with prior advice to the staff
of the Commission, as of January 1, 2001, (1) the former service companies in
the NiSource and CEG systems, NiSource Corporate Services Company ("Corporate
Services") and Columbia Energy Group Service Corporation ("CEGSC") were combined
and the resulting entity maintained the name of Corporate Services and the use
of the service agreement of CEGSC ("Service Agreement") and (2) the remaining
employees of the Shared Services Division of Columbia Gas of Ohio, Inc. became
employees of Corporate Services. The actions were taken in furtherance of the
integration of the NiSource and CEG systems pursuant to the Order.

     After review and discussion with the Commission's staff, NiSource and
Corporate Services have determined that the existing Service Agreement being
used by Corporate Services, together with related allocation methods and
factors, including revisions submitted to the Commission in 2000 under the 60
day letter procedure, is the most suitable basis for the on-going provision of
services by Corporate Services to NiSource System affiliates and will continue
to be used by Corporate Services. We believe that no further action of the

March 30, 2001
Page 2

Commission is required since there have been no changes in previously authorized
service arrangements. On behalf of NiSource and Corporate Services, we commit
that no material change will be made in the organization of Corporate Services,
the methods of allocating costs to associate companies, or in the scope or
character of the services to be rendered by Corporate Services, subject to
Section 13 of the Act, or any rule, regulation or order thereunder, unless and
until, Corporate Services has first given the Commission written notice of the
proposed change not less than 60 days prior to the proposed effectiveness of any
such change. A copy of the form of Service Agreement, together with its current
allocation methods and factors, as previously filed with, or submitted to, the
Commission by CEG and CEGSC, is also included as Exhibit A to this Rule 24

     Exhibit A - Form of Corporate Services' Service Agreement, including
allocation methods and factors.

                                        Very truly yours,

                                        THELEN REID & PRIEST, LLP
                                        Counsel for NiSource, Inc.
                                        and its Subsidiary Companies

                                        By:  /s/ William T. Baker, Jr.
                                                 William T. Baker, Jr.


cc:  Mr. Robert P. Wason
       Securities and Exchange Commission