Exhibit (5)(a)



            [Miller, Canfield, Paddock and Stone, P.L.C. Letterhead]

                                 March 31, 2003


Southern Michigan Bancorp, Inc.
51 West Pearl Street
Coldwater, Michigan 49036

Ladies and Gentlemen:

         With respect to the registration statement on Form S-8 (the
"Registration Statement") being filed today with the Securities and Exchange
Commission (the "Commission") by Southern Michigan Bancorp, Inc., a Michigan
corporation (the "Company"), for the purpose of registering under the Securities
Act of 1933, as amended (the "Act"), an indeterminate amount of interests in the
Southern Michigan Bancorp, Inc. 2000 Stock Option Plan (the "Plan") and 110,000
shares of the common stock, $2.50 par value, of the Company (the "Registered
Shares"), which may consist of shares already issued or newly issued shares.

         We have examined instruments, documents, and records which we deemed
relevant and necessary for the basis of our opinion hereinafter expressed. In
such examination, we have assumed the following: (a) the authenticity of
original documents and the genuineness of all signatures; (b) the conformity to
the originals of all documents submitted to us as copies; and (c) the truth,
accuracy, and completeness of the information, representations, and warranties
contained in the records, documents, instruments, and certificates we have
reviewed. Based upon our examination above, subject to the assumption and
qualifications stated and relying on statements of fact contained in the
documents we have reviewed, we are of the opinion that:

         1. The Registered Shares have been duly authorized.

         2. When the Registration Statement has become effective and Registered
Shares have been issued, sold and paid for in accordance with the Plan, such
Registered Shares will be validly issued, fully paid, and nonassessable.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement. In giving this consent, we do not thereby admit that we
are within the category of persons whose consent is required under Section 7 of
the Act or the rules and regulations of the Commission.


                                Very truly yours,

                                MILLER, CANFIELD, PADDOCK AND STONE, P.L.C.

                                /s/ MILLER, CANFIELD, PADDOCK AND STONE, P.L.C.
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