UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

FORM 11-K

{X} ANNUAL REPORT PURSUANT TO SECTION 15 (d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2003

OR

{ } TRANSITION REPORT PURSUANT TO SECTION 15 (d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from ____________ to _____________

Commission file number 0-12379

First Financial Bancorp Thrift Plan and Trust
300 High St.
Hamilton, OH 45011

First Financial Bancorp
300 High St.
Hamilton, OH 45011

Financial Statements and Supplemental Schedules

First Financial Bancorp Thrift Plan and Trust

Years ended December 31, 2003 and 2002
with Report of Independent Registered Public Accounting Firm

First Financial Bancorp Thrift Plan and Trust

Financial Statements and Supplemental Schedules

Years ended December 31, 2003 and 2002

Table of Contents

Report of Independent Registered Public Accounting Firm

Thrift Plan and Trust Administrative Committee
First Financial Bancorp

We have audited the accompanying statements of net assets available for benefits of the First Financial Bancorp Thrift Plan and Trust as of December 31, 2003 and 2002, and the related statements of changes in net assets available for benefits for the years then ended. These financial statements are the responsibility of the Plan’s management. Our responsibility is to express an opinion on these financial statements based on our audits.

We conducted our audits 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 the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements. An audit also includes assessing the accounting principles used and significant estimates made by management as well as evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements referred to above present fairly, in all material respects, the net assets available for benefits of the First Financial Bancorp Thrift Plan and Trust at December 31, 2003 and 2002, and changes in net assets available for benefits for the years then ended in conformity with U.S. generally accepted accounting principles.

Our audits were performed for the purpose of forming an opinion on the financial statements taken as a whole. The accompanying supplemental schedules of assets held as of December 31, 2003, and reportable transactions for the year then ended, are presented for the purposes of complying with the Department of Labor’s Rules and Regulations for Reporting and Disclosure under the Employee Retirement Income Security Act of 1974, and are not a required part of the basic financial statements. The Fund Information in the statement of net assets available for benefits and the statement of changes in net assets available for benefits is presented for purposes of additional analysis rather than to present the net assets available for benefits and changes in net assets available for benefits of each fund. The supplemental schedules and Fund Information have been subjected to the auditing procedures applied in our audits of the basic financial statements and, in our opinion, are fairly stated in all material respects in relation to the financial statements taken as a whole.

Cincinnati, Ohio
June 18, 2004

1

First Financial Bancorp Thrift Plan and Trust

Statement of Net Assets Available for Benefits, with Fund Information

December 31, 2003

See accompanying notes.

2

First Financial Bancorp Thrift Plan and Trust

See accompanying notes.

3

First Financial Bancorp Thrift Plan and Trust

Statement of Changes in Net Assets Available for Benefits, with Fund Information

December 31, 2003

See accompanying notes.

4

First Financial Bancorp Thrift Plan and Trust

Statement of Changes in Net Assets Available for Benefits, with Fund Information

December 31, 2002

See accompanying notes.

5

First Financial Bancorp Thrift Plan and Trust

Notes to Financial Statements

December 31, 2003

1. Description of the Plan

The following brief description of the First Financial Bancorp Thrift Plan and Trust (the Plan) is provided for general information purposes only. Participants should refer to the summary plan description for more information.

First Financial Bancorp (Bancorp) is the sponsor of the Plan.

General

The Plan is a defined-contribution plan, qualified under Section 401 of the Internal Revenue Code and is subject to the provisions of the Employee Retirement Income Security Act of 1974 (ERISA). The Plan covers substantially all employees of First Financial Bancorp (Plan Sponsor) and affiliates who have attained at least one year of service and are age twenty-one or older. The Plan is subject to the provisions of Section 401(k) of the Internal Revenue Code whereby the participants’ discretionary contributions would not be reportable as compensation for federal and state income tax purposes. The Plan is a single plan of a controlled group as defined in Code Sections 414(b) and 414(c).

Funding

Employer contributions to the Plan are equal to 50 percent of the employee’s contribution up to the first 6% of the participant’s deferrals. Employer contributions are initially invested in the First Financial Bancorp Common Stock Fund and are fully vested upon contribution to the Plan. As of March 31, 2002, participants have the option of directing the Employer contributions out of the stock fund on the first valuation date following the date of contribution. Although the sponsor has not expressed any intention to do so, it has the right under the Plan to discontinue contributions at any time and terminate the Plan, subject to provisions set forth in ERISA.

Effective January 1, 2003, participants may elect to make contributions to the Plan of up to 50 percent of their eligible salary on a before-tax basis. Prior to January 1, 2003, participants were permitted to make contributions to the Plan of up to 12 percent of their eligible salary on a before-tax basis. Prior to January 1, 1986, participants were permitted to contribute certain amounts on an after-tax basis. All contributions are fully vested when made and can be made to any of the investment options.

6

First Financial Bancorp Thrift Plan and Trust

Notes to Financial Statements (continued)

1. Description of the Plan (continued)

Participating Corporations

The terms of the Plan provide that any corporation that becomes a member of the controlled group may, with consent of Bancorp, adopt this plan for those employees which the Plan determines shall be eligible.

Benefit Payments

Participants may elect an in-service, non-hardship distribution comprised of the participant’s after tax contributions, employer contributions and the earnings of these accounts. Employer contributions withdrawn are limited to those made more than eight plan quarters prior to the quarter in which the withdrawal is being made. Such a withdrawal suspends the participant’s right to make contributions for one year.

Active employees may withdraw before-tax savings only if the participant can prove “financial hardship” as defined by the Plan Document. Any distribution of before-tax funds results in a one-year suspension of participation in the Plan. Earnings on the participant’s before-tax contributions are not eligible for distribution prior to termination or retirement.

Participants’ Accounts

Earnings are allocated on beginning account balances less any withdrawals during the quarter. A participant may elect to withdraw all or any part of his or her after-tax savings from the Plan. Such withdrawal suspends the participant’s rights to make future contributions for six months.

7

First Financial Bancorp Thrift Plan and Trust

Notes to Financial Statements (continued)

1. Description of the Plan (continued)

Participants’ Accounts (continued)

Employee contributions to the Plan may be allocated, in 5 percent increments, among any of the eight available funds, as follows:

8

First Financial Bancorp Thrift Plan and Trust

Notes to Financial Statements (continued)

1. Description of the Plan (continued)

Participants’ Accounts (continued)

9

First Financial Bancorp Thrift Plan and Trust

Notes to Financial Statements (continued)

1. Description of the Plan (continued)

Participants’ Accounts (continued)

Plan Termination

In the event of termination, the net assets will be distributed to participants and beneficiaries in proportion to their respective account balances, which are 100 percent vested.

2. Summary of Significant Accounting Policies

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.

Valuation of Investments

Separate trust accounts at First Financial Bank, National Association, a wholly-owned subsidiary of Bancorp, are used to hold and invest the Plan’s assets. Investments are stated at fair values based on quoted closing market prices obtained by the trustee from published market data. Security transactions are recorded on the trade date.

10

First Financial Bancorp Thrift Plan and Trust

Notes to Financial Statements (continued)

3. Investments

The Plan uses the average cost method for determining the cost of securities sold when determining realized gains and losses. The Plan’s investments (including investments bought, sold, and held during the year) appreciated fair value by $2,455,669 in 2003 and depreciated by $3,357,382 in 2002 as follows:

11

First Financial Bancorp Thrift Plan and Trust

Notes to Financial Statements (continued)

3. Investments (continued)

The fair value of individual investments that represent five (5) percent or more of the Plan’s net assets are as follows: