SECURITIES AND EXCHANGE COMMISSION

                             Washington, D. C. 20549

                                   FORM 10-K/A

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

                  For the fiscal year ended December 31, 2004

                         Commission file number 0-12422

                        MAINSOURCE FINANCIAL GROUP, INC.
             (Exact name of registrant as specified in its charter)

            Indiana                                             35-1562245
     (State or other jurisdiction                            (I.R.S. Employer
of incorporation or organization)                           Identification No.)

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

       Registrant's telephone number, including area code: (812) 663-0157

Securities registered pursuant to Section 12(b) of the Act:

                                      None

Securities registered pursuant to Section 12(g) of the Act:

                           Common shares, no-par value
                                (Title of Class)

         Indicate by check mark if disclosure of delinquent filers pursuant to
Item 405 of Regulation S-K is not contained herein, and will not be contained,
to the best of registrant's knowledge, in definitive proxy or information
statements incorporated by reference in Part III of this Form10-K or any
amendment to this Form 10-K. [ ]

         Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days. Yes [X] No [ ]
<PAGE>

         The aggregate market value (not necessarily a reliable indication of
the price at which more than a limited number of shares would trade) of the
voting stock held by non-affiliates of the registrant was $223,287,723 as of
June 30, 2004.

         Indicate by check mark whether the registrant is an accelerated filer
(as defined in Rule 12b-2 of the Act) Yes [X] No [ ]

         As of March 15, 2005, there were outstanding 11,534,056 common shares,
without par value, of the registrant.


<PAGE>

                                EXPLANATORY NOTE
        MainSource Financial Group, Inc. (the "Company") is filing this
Amendment No. 1 to Form 10-K to amend its Form 10-K for the year ended December
31, 2004, filed with the Securities and Exchange Commission on March 16, 2005
(the "Original Filing") in accordance with Securities and Exchange Commission
Release No. 34-50754, to:

         o replace Item 9A, "Controls and Procedures",

         o include management's report on internal control over financial
         reporting and the attestation report of Crowe Chizek and Company LLC,
         independent registered public accounting firm,

         o include a consent of Crowe Chizek and Company LLC, independent
         registered public accounting firm, with respect to its attestation
         report, and

         o replace Exhibits 31.1 and 31.2, certifications pursuant to Section
         302 of the Sarbanes-Oxley Act of 2002.  Except for the amendments
         described above, this Amendment No. 1 to Form 10-K does not modify or
         update in any way the Original Filing.

                                    PART III

ITEM 9A. CONTROLS AND PROCEDURES

Evaluation of Disclosure Controls and Procedures.

        Under the supervision and with the participation of the Company's
management, including the principal executive officer and principal financial
officer, the Company conducted an evaluation of the effectiveness of its
disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e)
promulgated under the Securities Exchange Act of 1934, as amended) as of the end
of the period covered by this report, or the Evaluation Date. Based on that
evaluation, the principal executive officer and principal financial officer
concluded that, as of the Evaluation Date, the Company's disclosure controls and
procedures are effective such that information required to be disclosed by the
Company in reports that it files with the SEC pursuant to the Securities
Exchange Act of 1934, as amended, is recorded, processed, summarized and
reported within the time periods specified in SEC rules and forms, subject to
management's completion of its assessment of internal control over financial
reporting.
<PAGE>

Internal Control Over Financial Reporting

1.       Management's Report on Internal Control Over Financial Reporting

         MainSource Financial Group (the "Corporation") is responsible for the
preparation, integrity, and fair presentation of the consolidated financial
statements included in this annual report. The consolidated financial statements
and notes included in this annual report have been prepared in conformity with
United States generally accepted accounting principles and necessarily include
some amounts that are based on management's best estimates and judgments.

         We, as management of MainSource Financial Group, are responsible for
establishing and maintaining effective internal control over financial reporting
that is designed to produce reliable financial statements in conformity with
Untied States generally accepted accounting principles. The system of internal
control over financial reporting as it relates to the financial statements is
evaluated for effectiveness by management and tested for reliability through a
program of internal audits and other management testing. Actions are taken to
correct potential deficiencies as they are identified. Because of its inherent
limitations, internal control over financial reporting may not prevent or detect
misstatements. Also, projections of any evaluation of effectiveness to future
periods are subject to the risk that controls may become inadequate because of
changes in conditions, or that the degree of compliance with the policies or
procedures may deteriorate.

         Management assessed the Corporation's system of internal control over
financial reporting as of December 31, 2004, in relation to criteria for
effective internal control over financial reporting as described in "Internal
Control--Integrated Framework" issued by the Committee of Sponsoring
Organizations of the Treadway Commission. This assessment excluded internal
control over financial reporting for Peoples Financial Corp. (PFC) as allowed by
the SEC for current year acquisitions. PFC was acquired on June 8, 2004 and
represented 7.5% of assets at December 31, 2004 and 4.9% of net income for 2004.
Based on this assessment, management concludes that as of December 31, 2004, its
system of internal controls over financial reporting is effective and meets the
criteria of the "Internal Control--Integrated Framework". Crowe Chizek and
Company LLC, independent registered public accounting firm, has issued an
attestation report dated March 10, 2005 on management's assessment of the
Corporation's internal control over financial reporting.

James L. Saner, Sr.                              Donald A. Benziger
President and Chief Executive Officer            Senior Vice President and Chief
                                                 Financial Officer

2.       Changes in Internal Control Over Financial Reporting

         Our management has evaluated our internal control over financial
reporting and there were no changes in our internal control over financial
reporting that occurred during the most recent fiscal quarter that have
materially affected, or are reasonably likely to materially affect, the
Company's internal control over financial reporting.
<PAGE>

Report of Independent Registered Public Accounting Firm on Internal Control
Over Financial Reporting

         We have audited management's assessment, included in the accompanying
Report on Management's Report on Internal Control Over Financial Reporting, that
MainSource Financial Group maintained effective internal control over financial
reporting as of December 31, 2004, based on criteria established in Internal
Control--Integrated Framework issued by the Committee of Sponsoring
Organizations of the Treadway Commission (COSO). MainSource Financial Group's
management is responsible for maintaining effective internal control over
financial reporting and for its assessment of the effectiveness of internal
control over financial reporting. Our responsibility is to express an opinion on
management's assessment and an opinion on the effectiveness of the Company's
internal control over financial reporting based on our audit.

         We conducted our audit in accordance with the standards of the Public
Company Accounting Oversight Board (United States). Those standards require that
we plan and perform the audit to obtain reasonable assurance about whether
effective internal control over financial reporting was maintained in all
material respects. Our audit included obtaining an understanding of internal
control over financial reporting, evaluating management's assessment, testing
and evaluating the design and operating effectiveness of internal control, and
performing such other procedures as we considered necessary in the
circumstances. We believe that our audit provides a reasonable basis for our
opinion.

         A company's internal control over financial reporting is a process
designed to provide reasonable assurance regarding the reliability of financial
reporting and the preparation of financial statements for external purposes in
accordance with generally accepted accounting principles. A company's internal
control over financial reporting includes those policies and procedures that (1)
pertain to the maintenance of records that, in reasonable detail, accurately and
fairly reflect the transactions and dispositions of the assets of the company;
(2) provide reasonable assurance that transactions are recorded as necessary to
permit preparation of financial statements in accordance with generally accepted
accounting principles, and that receipts and expenditures of the company are
being made only in accordance with authorizations of management and directors of
the company; and (3) provide reasonable assurance regarding prevention or timely
detection of unauthorized acquisition, use, or disposition of the company's
assets that could have a material effect on the financial statements.

         Because of its inherent limitations, internal control over financial
reporting may not prevent or detect misstatements. Also, projections of any
evaluation of effectiveness to future periods are subject to the risk that
controls may become inadequate because of changes in conditions, or that the
degree of compliance with the policies or procedures may deteriorate.

         As permitted, the Company excluded the bank acquired in June 2004
(Peoples Financial Corporation) from the scope of management's report on
internal control over financial reporting. As such, this entity has also been
excluded from the scope of our audit of internal control over financial
reporting.
<PAGE>

         In our opinion, management's assessment that MainSource Financial Group
maintained effective internal control over financial reporting as of December
31, 2004, is fairly stated, in all material respects, based on criteria
established in Internal Control--Integrated Framework issued by the Committee of
Sponsoring Organizations of the Treadway Commission (COSO).

         Also in our opinion, MainSource Financial Group maintained, in all
material respects, effective internal control over financial reporting as of
December 31, 2004, based on criteria established in Internal Control--Integrated
Framework issued by the Committee of Sponsoring Organizations of the Treadway
Commission (COSO).

         We have also audited, in accordance with the standards of the Public
Company Accounting Oversight Board (United States), the consolidated balance
sheets as of December 31, 2004 and 2003, and the related consolidated statements
of income, shareholders' equity, and cash flows for each of the three years in
the period ended December 31, 2004 of MainSource Financial Group and our report
dated February 11, 2005, except for Note 2 with respect to the pending
acquisition, as to which the date is March 8, 2005, expressed an unqualified
opinion on the consolidated financial statements.

/s/ Crowe Chizek and Company LLC

Indianapolis, Indiana
March 10, 2005

                                     PART IV

ITEM 15--EXHIBITS, FINANCIAL STATEMENT SCHEDULES

(a) 3. Exhibits:

     3.1 Restated Articles of Incorporation (incorporated by reference to
Exhibit 3.1 to the Annual Report on Form 10-K of the registrant for the fiscal
year ended December 31, 2003 filed March 12, 2004 with the Commission
(Commission File No. 0-12422)).

     3.2 Amended and Restated Bylaws dated April 28, 1998 (incorporated by
reference to Exhibit 3.2 to the Annual Report on Form 10-K of the registrant for
the fiscal year ended December 31,1998 filed March 29, 1999 with the Commission
(Commission File No. 0-12422)).

     4.1 Indenture dated as of December 19, 2002 between the Registrant, as
issuer, and State Street Bank and Trust Company of Connecticut, N.A., as
trustee, re: floating rate junior subordinated deferrable interest debentures
due 2032 (incorporated by reference to Exhibit 4.6 to the Annual Report on Form
10-K of the registrant for the fiscal year ended December 31, 2002 filed March
28, 2003 with the Commission (Commission File No. 0-12422)).

     4.2 Amended and Restated Declaration of Trust dated as of December 19, 2002
among State Street Bank and Trust Company of Connecticut, N.A., as institutional
trustee, the Registrant, as sponsor, and James L. Saner Sr., Donald A. Benziger
and James M. Anderson, as administrators (incorporated by reference to Exhibit
4.7 to the Annual Report on Form 10-K of the registrant for the fiscal year
ended December 31, 2002 filed March 28, 2003 with the Commission (Commission
File No. 0-12422)).
<PAGE>

     4.3 Guarantee Agreement dated as of December 19, 2002 between the
Registrant, and State Street Bank and Trust Company of Connecticut, N.A
(incorporated by reference to Exhibit 4.8 to the Annual Report on Form 10-K of
the registrant for the fiscal year ended December 31, 2002 filed March 28, 2003
with the Commission (Commission File No. 0-12422)).

     4.4 Indenture dated as of April 1, 2003 between the Registrant, as issuer,
and U.S. Bank, N.A., as trustee, re: floating rate junior subordinated
deferrable interest debentures due 2033 (incorporated by reference to Exhibit
4.1 to the Quarterly Report on Form 10-Q of the registrant for the quarter ended
June 30, 2003 filed August 14, 2003 with the Commission (Commission File No.
0-12422)).

     4.5 Amended and Restated Declaration of Trust dated as of April 1, 2003
among U.S. Bank, N.A., as institutional trustee, the Registrant, as sponsor, and
James L. Saner Sr., Donald A. Benziger and James M. Anderson, as administrators
(incorporated by reference to Exhibit 4.2 to the Quarterly Report on Form 10-Q
of the registrant for the quarter ended June 30, 2003 filed August 14, 2003 with
the Commission (Commission File No. 0-12422)).

     4.6 Guarantee Agreement dated as of April 1, 2003 between the Registrant,
and U.S. Bank, N.A (incorporated by reference to Exhibit 4.3 to the Quarterly
Report on Form 10-Q of the registrant for the quarter ended June 30, 2003 filed
August 14, 2003 with the Commission (Commission File No. 0-12422)).

     4.7 Indenture dated as of June 12, 2003 between the Registrant, as issuer,
and The Bank of New York, as trustee, re: rate junior subordinated deferrable
interest debentures due (incorporated by reference to Exhibit 4.4 to the
Quarterly Report on Form 10-Q of the registrant for the quarter ended June 30,
2003 filed August 14, 2003 with the Commission (Commission File No. 0-12422)).

     4.8 Amended and Restated Declaration of Trust dated as of June 12, 2003
among The Bank of New York, as institutional trustee, the Registrant, as
sponsor, and James L. Saner Sr., Donald A. Benziger and James M. Anderson, as
administrators (incorporated by reference to Exhibit 4.5 to the Quarterly Report
on Form 10-Q of the registrant for the quarter ended June 30, 2003 filed August
14, 2003 with the Commission (Commission File No. 0-12422)).

     4.9 Guarantee Agreement dated as of June 12, 2003 between the Registrant,
and The Bank of New York (incorporated by reference to Exhibit 4.6 to the
Quarterly Report on Form 10-Q of the registrant for the quarter ended June 30,
2003 filed August 14, 2003 with the Commission (Commission File No. 0-12422)).

     10.1 Registrant's 2003 Stock Option Plan (incorporated by reference to
Exhibit 10.1 to the Annual Report on Form 10-K of the registrant for the fiscal
year ended December 31, 2003 filed March 12, 2004 with the Commission
(Commission File No. 0-12422)).*
<PAGE>

     10.2 Form of Stock Option Agreement Under 2003 Stock Option Plan for
Directors of Registrant dated May 19, 2003 (incorporated by reference to Exhibit
10.2 to the Annual Report on Form 10-K of the registrant for the fiscal year
ended December 31, 2003 filed March 12, 2004 with the Commission (Commission
File No. 0-12422)).*

     10.3 Form of Stock Option Agreement Under 2003 Stock Option Plan for
Officers of Registrant (incorporated by reference to Exhibit 10.1 to the Report
on Form 8-K of the registrant filed February 24, 2005 with the Commission
(Commission File No. 0-12422)).*

     10.4 Form of Executive Severance Agreement dated January 16, 2001 between
the Registrant and James L. Saner, Sr. (incorporated by reference to Exhibit
10.2 to the Annual Report on Form 10-K of the registrant for the fiscal year
ended December 31, 2000 filed March 30, 2001 with the
Commission (Commission File No. 0-12422)).*

     10.5 Form of Executive Severance Agreement dated January 16, 2001 between
the Registrant and Donald A. Benziger (incorporated by reference to Exhibit 10.2
to the Annual Report on Form 10-K of the registrant for the fiscal year ended
December 31, 2000 filed March 30, 2001 with the Commission (Commission File No.
0-12422)).*

     10.6 Form of Executive Severance Agreement dated January 16, 2001 between
the Registrant and John C. Parker (incorporated by reference to Exhibit 10.4 to
the Annual Report on Form 10-K of the registrant for the fiscal year ended
December 31, 2002 filed March 28, 2003 with the Commission (Commission File No.
0-12422)).*

     10.7 Form of Indemnification Agreement for Directors and Certain Officers
of Registrant (incorporated by reference to Exhibit 10.1 to the Report on Form
8-K of the registrant filed February 24, 2005 with the Commission (Commission
File No. 0-12422)).

     14 Code of Ethical Conduct (incorporated by reference to Exhibit 14 to the
Annual Report on Form 10-K of the registrant for the fiscal year ended December
31, 2003 filed March 12, 2004 with the Commission (Commission File No.
0-12422)).

     21 List of subsidiaries of the Registrant.**

     23.1 Consent of Crowe Chizek and Company LLC**

     23.2 Consent of Crowe Chizek and Company LLC***

     31.1 Certification pursuant to Section 302 of Sarbanes-Oxley Act of 2002
          by Chief Executive Officer***

     31.2 Certification pursuant to Section 302 of Sarbanes-Oxley Act of 2002
          by Chief Financial Officer***
<PAGE>
     The following exhibits accompany this periodic report pursuant to Section
906 of the Sarbanes-Oxley Act of 2002 (the "2002 Act"). These exhibits shall be
deemed only to accompany this periodic report and are not part of this periodic
report, shall not be deemed filed for purposes of the Securities Exchange Act of
1934, and may not be for any purpose other than compliance with the 2002 Act.

     32.1 Certification pursuant to Section 906 of the Sarbanes-Oxley Act of
          2002, by Chief Executive Officer**

     32.2 Certification pursuant to Section 906 of the Sarbanes-Oxley Act of
          2002, by Chief Financial Officer**

* A management contract or compensatory agreement.

** Previously filed as an exhibit to the Company's Annual Report on Form 10-K
for the year ended December 31, 2004.

*** Filed herewith.
                                   SIGNATURES

         Pursuant to the requirements of Section 13 or 15(d) 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, on the 7th day of
April, 2005.

                        MAINSOURCE FINANCIAL GROUP, INC.

                        /s/ James L. Saner, Sr.
                       ------------------------------------------------------
                        James L. Saner, Sr., President
                        And Chief Executive Officer