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): December 27, 2005

                        MainSource Financial Group, Inc.
             (Exact name of registrant as specified in its charter)

   Indiana                              0-12422                  35-1562245
State or Other Jurisdiction of      Commission File No.        I.R.S. Employer
Incorporation or Organization                              Identification Number



                               201 North Broadway
                            Greensburg, Indiana 47240
                    (Address of principal executive offices)

                                 (812) 663-0157
                             (Registrant's Telephone
                                     Number,
                              Including Area Code)

                                       N/A
          (Former Name or Former Address, if Changed Since Last Report)

     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:

     __ Written communications pursuant to Rule 425 under the Securities Act
        (17 CFR  230.425)
     __ Soliciting  material  pursuant to Rule 14a-12 under the Exchange Act
        (17 CFR  240.14a-12)
     __ Pre-commencement communications pursuant to Rule 14d-2(b)  under  the
        Exchange Act (17 CFR 240.14d-2(b))
     __ 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 December 27,  2005,  MainSource  Financial  Group,  Inc.  issued a press
release  announcing a repositioning  of its investment  securities  portfolio to
eliminate certain under-performing  investment securities.  The press release is
attached  hereto as an exhibit to this  Current  Report on Form 8-K and is being
furnished  pursuant to this Item 7.01 as Exhibit 99.1 to this Current  Report on
Form 8-K.

Item 9.01.  Financial Statements and Exhibits

    (c) The following exhibit is furnished with this report:

         Exhibit No.       Description

         99.1              MainSource Financial Group, Inc.'s press release
                           dated December 27, 2005.

                                   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.

                                      MAINSOURCE FINANCIAL GROUP, INC.

Date:    December 27, 2005            By:  /s/ James L. Saner, Sr.
                                           -----------------------
                                           James L. Saner, Sr.
                                           President and Chief Executive Officer