UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the
Securities Exchange Act of 1934

Date of Report (Date of earliest event reported):  May 30, 2012

SOUTHERN MICHIGAN BANCORP, INC.
(Exact Name of Registrant as
Specified in Charter)

Michigan
(State or Other Jurisdiction
of Incorporation) 000-49722
(Commission
File Number) 38-2407501
(IRS Employer
Identification No.)

51 West Pearl Street
Coldwater, Michigan
(Address of Principal Executive Offices)
49036
(Zip Code)

Registrant's telephone number,
including area code:  (517) 279-5500

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the Registrant under any of the following provisions:

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425).

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12).

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)).

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)).

Item 7.01. Regulation FD Disclosure.

          On May 30, 2012, Southern Michigan Bancorp, Inc. mailed to its shareholders the letter furnished with this report as Exhibit 99.1, which is here incorporated by reference. This Report and the Exhibit are furnished to, and not filed with, the Commission.

Item 9.01.	Financial Statements and Exhibits.
	(d)	Exhibits:
	99.1	Letter mailed May 30, 2012.

SIGNATURES

          Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

Date:  May 30, 2012	SOUTHERN MICHIGAN BANCORP, INC.
	By	/s/ Danice L. Chartrand
		Danice L. Chartrand Senior Vice President, Chief Financial Officer, Secretary, and Treasurer

EXHIBIT INDEX

Exhibit Number	Document
99.1	Letter mailed May 30, 2012.