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                                                                     EXHIBIT 5.1
[MCN ENERGY GROUP INC. LETTERHEAD]

February 27, 1998

MCN Energy Group Inc.
500 Griswold Street
Detroit, MI 48226

Ladies and Gentlemen:

     I am acting as counsel for MCN Energy Group Inc. ("MCN") and MCN
Investment Corporation ("MCN Investment"), both Michigan corporations, in
connection with the registration of up to $700,000,000 of Debt Securities to be
offered on a continuous or delayed basis pursuant to the provisions of Rule
415. The Debt Securities are being registered under the Securities Act of 1933,
as amended (the "1933 Act"), by a Registration Statement on Form S-3 filed with
the Securities and Exchange Commission on February 27, 1998. Capitalized terms
used but not defined herein are used as defined in the Registration Statement.

     In preparation for rendering my opinion hereafter expressed, I have
examined the originals or copies, certified to my satisfaction, of such
corporate records and other documents and certificates as I have deemed
necessary.

     Based on the above, I am of the opinion that:

     1.   MCN and MCN Investment are corporations duly organized and validly
          existing under and pursuant to the laws of the State of Michigan.

     2.   The Debt Securities when sold, will be legally issued by MCN
          Investment, duly authorized, fully paid and nonassessable and will be
          binding obligations of MCN Investment.

     I hereby consent to the use of this opinion as Exhibit 5-1 to the
Registration Statement and to the use of my name under the caption "Validity of
Securities" in the Registration Statement. This consent may be incorporated by
reference into any registration statement of MCN and MCN Investment relating to
the debt securities included in this Registration Statement on Form S-3 filed
after the date hereof pursuant to Rule 462(b) under the 1933 Act.

Very truly yours,

Daniel L. Schiffer