<PAGE>

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

                                   FORM 10-KSB

(Mark one)

[X]      ANNUAL REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT
         OF 1934

         For the fiscal year ended December 31, 2003

[ ]      TRANSITION REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
         ACT OF 1934

         For the transition period from            to
                                        ----------    -------

                           Commission File No. 0-28648

                           OHIO STATE BANCSHARES, INC.
                 ----------------------------------------------
                 (Name of small business issuer in its charter)

           OHIO                                           34-1816546
-------------------------------             ------------------------------------
(State or other jurisdiction of             (I.R.S. Employer Identification No.)
incorporation or organization)

   111 South Main Street, Marion, Ohio                       43302
----------------------------------------                   ----------
(Address of principal executive offices)                   (Zip code)

                                 (740) 387-2265
                           --------------------------
                          (Issuer's telephone number)

Securities registered under Section 12(b) of the Exchange Act:

        Title of each class            Name of each exchange on which registered
        -------------------            -----------------------------------------
              None                                      None

Securities registered under Section 12(g) of the Exchange Act:

                         Common Shares, $10.00 par value
                                (Title of class)

Check whether the issuer (1) filed all reports required to be filed by Section
13 or 15(d) of the Exchange Act during the past 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 [ ]

Check if there is no disclosure of delinquent filers in response to Item 405 of
Regulation S-B is not contained in this form, and no disclosure will be
contained, to the best of registrant's knowledge, in definitive proxy or
information statements incorporated by reference in Part III of this Form 10-KSB
or any amendment to this Form 10-KSB. [ ]

Issuer's revenue for the year ended December 31, 2003 was: $6,984,668.

The aggregate market value of the Issuer's voting stock held by nonaffiliates of
the Issuer as of March 15, 2004 based on the trade price of $77.00 was
$10,191,181.

At March 15, 2004, there were issued and outstanding 190,000 of the Issuer's
Common Shares.

                       DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Issuer's 2003 Annual Report to security holders are incorporated
by reference into Item 1, Item 6 and Item 7 and are attached as exhibit 13.
Portions of the Issuer's Proxy Statement to be separately filed and dated
approximately March 26, 2004, are incorporated by reference into Item 9, Item
10, Item 11, Item 12 and Item 14.

Transitional Small Business Disclosure Form (check one): Yes [X]   No [ ]

<PAGE>

                                      INDEX

                                   FORM 10-KSB

<TABLE>
<S>                                                                                <C>
PART I

   ITEM 1.   Description of Business.............................................   3

   ITEM 2.   Description of Property.............................................   4

   ITEM 3.   Legal Proceedings...................................................   4

   ITEM 4.   Submission of Matters to a Vote of Security Holders.................   4

PART II

   ITEM 5.   Market for Common Equity and Related Shareholder Matters............   5

   ITEM 6.   Management's Discussion and Analysis of Financial Condition
             and Results of Operations...........................................   5

   ITEM 7.   Financial Statements................................................   5

   ITEM 8.   Changes in and Disagreements with Accountants on
             Accounting and Financial Disclosure.................................   5

   ITEM 8a.  Controls and Procedures.............................................   6

PART III

   ITEM 9.   Directors, Executive Officers, Promoters and Control Persons;
             Compliance with Section 16(a) of the Exchange Act...................   7

   ITEM 10.  Executive Compensation..............................................   7

   ITEM 11.  Security Ownership of Certain Beneficial Owners and Management
             and Related Stockholder Matters.....................................   7

   ITEM 12.  Certain Relationships and Related Transactions......................   8

   ITEM 13.  Exhibits and Reports on Form 8-K....................................   9

   ITEM 14.  Principle Accountant Fees and Services..............................  10

SIGNATURES   ....................................................................  11
</TABLE>

                                       2
<PAGE>

                                     PART I

ITEM 1 - DESCRIPTION OF BUSINESS

BUSINESS

At the annual shareholders' meeting held on April 13, 1995, The Marion Bank's
("Bank") shareholders approved a plan of reorganization whereby they would
exchange their shares of Bank stock for the common stock of Ohio State
Bancshares, Inc. ("OSB"), together referred to as the Corporation. OSB received
approval from the Board of Governors of the Federal Reserve System during early
1996 and the reorganization was consummated on May 16, 1996. The principal
business of OSB is presently to operate the Bank, which is a wholly-owned
subsidiary and its principal asset. OSB and the main office of the Bank are
located at 111 South Main Street, Marion, Ohio 43302. The Corporation's
telephone number is (740) 387-2265.

Although wholly-owned by OSB, the Bank functions as an independent community
bank. The Bank was chartered as an Ohio banking corporation on March 24, 1988
and commenced operations on August 23, 1988. The Bank offers a full range of
commercial banking services, including commercial loans, real estate loans and
various types of consumer loans; checking, savings and time deposits; money
market accounts; travelers checks; pre-approved overdraft protection; safe
deposit boxes and other customary nondeposit banking services. The Bank is an
agent for Visa credit cards and is a merchant depository for cardholder sales
drafts. At the present time, the Bank does not have a trust department, but can
provide access to this service through correspondent banks. The Bank is a member
of 24-hour automated teller networks. It also offers two lanes of drive-up
banking services at each banking location.

The nature of the Bank allows for full diversification of depositors and
borrowers so it is not dependent upon a single or a few customers. Most of the
Bank's deposits are attracted from individuals and business related sources. No
material portion of the Bank's loans are concentrated within a single industry
or group of related industries. The Corporation is not aware of any exposure to
material costs associated with environmental hazardous waste cleanup. Bank loan
procedures require EPA studies be obtained by Bank management prior to approving
any commercial real estate loan with such potential risk.

SUPERVISION AND REGULATION

REGULATION OF THE CORPORATION: OSB is a registered bank holding company
organized under the laws of the State of Ohio. As such, OSB is subject to the
laws of the State of Ohio and is under the jurisdiction of the Securities Act of
1933, as amended, and various Securities and Exchange Commission rules and
regulations relating to the offering and sale of its securities. The Corporation
is also subject to regulation under the Bank Holding Company Act of 1956 as
amended. The Federal Reserve Board regulates bank holding companies and may
examine or inspect the books and records of OSB and the Bank.

REGULATION OF THE BANK: The Bank is chartered in the State of Ohio and regulated
by the Ohio Department of Commerce, Division of Financial Institutions and the
Federal Deposit Insurance Corporation. These regulatory agencies have the
authority to examine the books and records of the Bank, and the Bank is subject
to their rules and regulations.

EMPLOYEES

As of December 31, 2003, the Bank employed 24 full-time and 5 part-time
employees.

                                       3
<PAGE>

STATISTICAL DISCLOSURES BY BANK HOLDING COMPANIES

The statistical disclosures required by bank holding companies is incorporated
by reference and are included on page 2 under the heading Summary of Selected
Financial Data, in Footnotes 3, 5 and 6 to the consolidated financial statements
on pages 12 through 15 and in the managements discussion and analysis on pages
22 through 30 of the Corporation's 2003 Annual Report and is attached as Exhibit
13.

Nonaccrual loans for the Bank were $483,314 at December 31, 2003. If these loans
had been performing in accordance with their original terms, and not placed on
nonaccrual status, an additional $34,546 would have been recognized as interest
income in 2003. Additional information regarding nonaccrual, past due and
restructured loans is incorporated by reference and is included on pages 13 and
26 of the Corporation's 2003 Annual Report and is attached as Exhibit 13.

ITEM 2 - DESCRIPTION OF PROPERTY

The Bank's main office is located in downtown Marion, Ohio. The Bank opened a
full service branch at 220 Richland Road, Marion, Ohio in December 1996. The
branch provides a full range of financial services including two drive-through
lanes, a full service ATM machine and night deposit capabilities. The branch
expanded the Bank into the eastern part of Marion to better serve its existing
customers in that area. The Bank owns all premises related to its main office
and leases its branch under an operating lease. All such premises are suitable
for their intended use. Management believes all properties are in excellent
condition and are adequately covered by insurance.

ITEM 3 - LEGAL PROCEEDINGS

Corporation management is aware of no pending or threatened litigation in which
the Corporation faces potential loss or exposure which will materially affect
the consolidated financial statements or involves a claim for damages exceeding
ten percent of the assets of the Corporation.

ITEM 4 - SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

No matters were submitted to a vote of security holders during the fourth
quarter of the Corporation's December 31, 2003 fiscal year end.

                                       4
<PAGE>

                                     PART II

ITEM 5 - MARKET FOR COMMON EQUITY AND RELATED SHAREHOLDER MATTERS

The common stock of the Corporation trades infrequently and is not traded on any
established securities market. Parties interested in buying or selling the
Corporation's stock are generally referred to Community Banc Investments, New
Concord, Ohio (CBI).

For 2003 and 2002, bid and ask quotations were obtained from CBI, which handles
a limited amount of the Corporation's stock transactions. The quotations are
inter-dealer prices, without retail markup, markdown or commission and may not
represent actual transactions.

<TABLE>
<CAPTION>
  2003     Low Bid   High Bid   Low Ask   High Ask
  ----     -------   --------   -------   --------
<S>        <C>       <C>        <C>       <C>
1st Qtr.   $ 69.00   $  69.00   $ 72.00   $  72.00
2nd Qtr.     69.00      72.00     72.00      75.00
3rd Qtr.     72.00      72.00     75.00      75.00
4th Qtr.     72.00      77.00     75.00      80.00

  2002

1st Qtr.   $ 62.00   $  62.00   $ 64.00   $  64.00
2nd Qtr.     62.00      64.00     64.00      64.00
3rd Qtr.     64.00      66.00     67.00      69.00
4th Qtr.     66.00      69.00     69.00      72.00
</TABLE>

Management does not have knowledge of the prices paid in all transactions and
has not verified the accuracy of those prices that have been reported. Because
of the lack of an established market for the Corporation's stock, these prices
may not reflect the prices at which the stock would trade in an active market.

The Corporation has 500,000 authorized and 190,000 outstanding shares of common
stock held by approximately 532 shareholders as of December 31, 2003. The
Corporation paid cash dividends of $0.40 and $0.30 per share in June and
December of 2003 and 2002, resulting in a total amount of $0.80 and $0.60 per
share in 2003 and 2002.

ITEM 6 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
OF OPERATIONS

Information concerning Management's Discussion and Analysis of Financial
Condition and Results of Operations appears on pages 22 through 34 of the 2003
Annual Report and is attached as exhibit 13.

ITEM 7 - FINANCIAL STATEMENTS

Information concerning the audited consolidated financial statements of the
Corporation for 2003 and 2002 appears on pages 3 through 21 of the 2003 Annual
Report and is attached as exhibit 13.

ITEM 8 - CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND
  FINANCIAL DISCLOSURE

No changes in or disagreements with the Corporation's independent accountants on
accounting and financial disclosure have occurred during the two most recent
fiscal years.

                                       5
<PAGE>

ITEM 8a - CONTROLS AND PROCEDURES

Within the 90-day period prior to the filing date of this report, an evaluation
was carried out under the supervision and with the participation of
Corporation's management, including our Chief Executive Officer and Chief
Financial Officer, of the effectiveness of our disclosure controls and
procedures (as defined in Exchange Act Rules 13a-14(c) and 15d-14(c) under the
Securities Exchange Act of 1934). Based on their evaluation, our Chief Executive
Officer and Chief Financial Officer have concluded that the Corporation's
disclosure controls and procedures are, to the best of their knowledge,
effective to ensure that information required to be disclosed by the Corporation
in reports that it files or submits under the Exchange Act is recorded,
processed, summarized and reported within the time periods specified in
Securities and Exchange Commission rules and forms. Subsequent to the date of
their evaluation, our Chief Executive Officer and Chief Financial Officer have
concluded that there were no significant changes in Corporation's internal
controls or in other factors that could significantly affect its internal
controls, including any corrective actions with regard to significant
deficiencies and material weaknesses.

                                       6
<PAGE>

                                    PART III

ITEM 9 - DIRECTORS, EXECUTIVE OFFICERS, PROMOTERS AND CONTROL PERSONS;
  COMPLIANCE WITH SECTION 16(a) OF THE EXCHANGE ACT

Information concerning Directors and Executive Officers of the Corporation
appears on pages 3 through 5 under the captions Election of Directors and
Securities Ownership of Certain Beneficial Owners and Management and on page 13
under the captions Compliance With Section 16(A) of the Securities Exchange Act
of 1934 in the Corporation's Definitive Proxy Statement dated March 26, 2004 for
the Annual Meeting of Shareholders to be held on April 15, 2004, and is
incorporated herein by reference.

The Board of Directors has determined that the Corporation does not have an
audit committee financial expert serving on its audit committee. However, the
Board of Directors has determined that each audit committee member has
sufficient knowledge in financial and auditing matters to serve on the
committee. At this time, the Board does not believe it is necessary to actively
search for an outside person to serve on the Board who would qualify as a
financial expert.

The Board of Directors of the Corporation adopted a Code of Business Conduct and
Ethics (the "Code") at its meeting on March 18, 2004. While the Sarbanes-Oxley
Act of 2002 mandates the adoption of a code of ethics for the most senior
executive officers of all public companies, the Code adopted by the
Corporation's Board of Directors is broader in the activities covered and
applies to all officers, directors and employees of the Corporation and the
Bank, including the chief executive officer, chief financial officer, principal
accounting officer and other senior officers performing accounting, auditing,
financial management or similar functions. The administration of the Code has
been delegated to the Audit Committee of the Board of Directors, a Committee
comprised entirely of "independent directors." The Code addresses topics such as
compliance with laws and regulations, honest and ethical conduct, conflicts of
interest, confidentiality and protection of Corporation assets, fair dealing and
accurate and timely periodic reports, and also provides for enforcement
mechanisms. The Board and management of the Corporation intends to continue to
monitor not only the developing legal requirements in this area, but also the
best practices of comparable companies, to assure that the Corporation maintains
sound corporate governance practices in the future.

A copy of the Corporation's Code is available on the website of the Bank
(www.themarionbank.com.) In addition, a copy of the Code is available to any
shareholder free of charge upon request. Shareholders desiring a copy of the
Code should address written requests to Mr. Gary Pendleton, President, Chief
Executive Officer, Ohio State Bancshares, Inc., 111 S. Main Street, Marion, Ohio
43302.

ITEM 10 - EXECUTIVE COMPENSATION

Information concerning executive compensation appears on page 9 under the
captions Executive Compensation and Other Information in the Corporation's
Definitive Proxy Statement dated March 26, 2004 for the Annual Meeting of
Shareholders to be held on April 15, 2004, and is incorporated herein by
reference.

ITEM 11 - SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS
  AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS

Information concerning security ownership of certain beneficial owners and
management is contained on pages 3 through 5 under the captions Election of
Directors and Securities Ownership of Certain Beneficial Owners and Management
in the Corporation's Definitive Proxy Statement dated March 26, 2004 for the
Annual Meeting of Shareholders to be held on April 15, 2004, and is incorporated
herein by reference.

                                       7

<PAGE>

ITEM 12 - CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

Information concerning certain relationships and related transactions is
contained on page 12 under the caption Certain Transactions in the Corporation's
Definitive Proxy Statement dated March 26, 2004 for the Annual Meeting of
Shareholders to be held on April 15, 2004 and is incorporated herein by
reference.

                                       8

<PAGE>

ITEM 13 - EXHIBITS LIST AND REPORTS ON FORM 8-K

(a)      EXHIBITS

<TABLE>
<CAPTION>
                                                                             Reference to
Regulation S-B                                                               Prior Filing
    Exhibit                                                                 Exhibit Number
    Number                     Description of Document                      Attached Hereto     Date Filed
--------------         -------------------------------------------          ---------------    ------------
<S>                    <C>                                                  <C>                <C>
     3.1               Amended Articles of Incorporation of
                        the Corporation                                           *             03/29/2000

     3.2               Code of Regulations of the Corporation                     *             03/29/2000

     4                 Form of Shares Certificate of Common Shares               ***

     10.1              Lease Agreement Between Henney and
                        Cooper, Inc. and The Marion Bank for
                        Branch on Richland Road in Marion, Ohio                   *             03/24/1997

     10.2              Executive Indexed Salary Continuation
                        Plan Agreement for President                              *             03/24/1997

     10.3              Executive Indexed Salary Continuation
                        Plan Agreement for Executive Officers                     *             03/27/1998

     10.4              Executive Change of Control Agreement                      *             03/30/2001

     13                Ohio State Bancshares 2003 Annual Report               Attached

     20                Proxy Statement for the 2003 Annual                       **
                        Meeting of the Shareholders

     21                Subsidiaries of the Registrant                           ***

     31(a)             Chief Executive Officer Certification                  Attached

     31(b)             Chief Financial Officer Certification                  Attached

     32(a)             Chief Executive Officer Certification                  Attached

     32(b)             Chief Financial Officer Certification                  Attached

     99.1              Safe Harbor under the Private Securities
                        Litigation Reform Act of 1995                             *             03/26/1999
</TABLE>

*    Indicates documents which have been previously filed as separate pages of
     the Corporation's annual report on Form 10-KSB in prior years. The dates
     listed represent the filing dates. All of such previously filed documents
     are hereby incorporated by reference in accordance with Item 601 of
     Regulation S-B. Such documents are available to shareholders without charge
     upon request.

**   The indicated exhibit was separately filed by the Corporation and such
     document is incorporated herein by reference.

***  Indicates documents which have been previously filed as part of the
     Issuer's Registration Statement under the Securities Act of 1933 on Form
     S-4 (file number 33-75866) dated April 18, 1994 and amended and declared
     effective April 16, 1995. All of such previously filed documents are hereby
     incorporated by reference in accordance with Item 601 of Regulation S-B.
     Such documents are available to shareholders without charge upon request
     from the Issuer.

(b)      REPORTS ON FORM 8-K

No reports on Form 8-K were filed during the last quarter of the period covered
by this report.

                                       9

<PAGE>

ITEM 14 - PRINCIPLE ACCOUNTANT FEES AND SERVICES

Information concerning principle accounting firm fees appears on page 9 under
the captions Principle Accounting Firm Fees in the Corporation's Definitive
Proxy Statement dated March 26, 2004 for the Annual Meeting of Shareholders to
be held on April 15, 2004, and is incorporated herein by reference.

                                       10

<PAGE>

                                   SIGNATURES

In accordance with Section 13 or 15(d) of the Exchange Act, the registrant
caused this report to be signed on its behalf by the undersigned, thereunto duly
authorized.

                                           OHIO STATE BANCSHARES, INC.

     March 29, 2004                        By:    /s/ GARY E. PENDLETON
--------------------------                    ---------------------------------
           Date                                   Gary E. Pendleton, President

In accordance with the Exchange Act, this report has been signed below by the
following persons on behalf of registrant and in the capacities indicated on
April 17, 2003.

<TABLE>
<CAPTION>
                  Signatures                                        Signatures
--------------------------------------------           -------------------------------------
<S>                                                    <C>
     /s/ GARY E. PENDLETON                                   /s/ LLOYD L. JOHNSTON
--------------------------------------------           -------------------------------------
Gary E. Pendleton                                      Lloyd L. Johnston
President and Chief Executive Officer, Director        Director

     /s/ THEODORE L. GRAHAM                                  /s/ F. WINTON LACKEY
--------------------------------------------           -------------------------------------
Theodore L. Graham                                     F. Winton Lackey
Director                                               Director

     /s/ FRED K. WHITE                                       /s/ THURMAN R. MATHEWS
--------------------------------------------           -------------------------------------
Fred K. White                                          Thurman R. Mathews
Director, Chairman of the Board                        Director

     /s/ SAMUEL J. BIRNBAUM                                  /s/ PETER B. MILLER
--------------------------------------------           -------------------------------------
Samuel J. Birnbaum                                     Peter B. Miller
Director                                               Director

     /s/ LOIS J. FISHER
--------------------------------------------
Lois J. Fisher
Director
</TABLE>

                                       11