Exhibit 15 -Letter Re: Unaudited Interim Financial Information

The Board of Directors
F.N.B. Corporation

We are aware of the incorporation by reference in the following Registration
Statements and in their related Prospectuses, of our report dated April 17,
2003, relating to the unaudited consolidated interim financial statements of
F.N.B. Corporation and subsidiaries that are included in its Form 10-Q for the
quarter ended March 31, 2003:

1.  Registration Statement on Form S-8 relating to F.N.B. Corporation 1990 Stock
    Option Plan (File #33-78114).

2.  Registration Statement on Form S-8 relating to F.N.B. Corporation Restricted
    Stock Bonus Plan (File #33-78134).

3.  Registration Statement on Form S-8 relating to F.N.B. Corporation 1996 Stock
    Option Plan (File #333-03489).

4.  Registration Statement on Form S-8 relating to F.N.B. Corporation Restricted
    Stock and Incentive Bonus Plan (File #333-03493).

5.  Registration Statement on Form S-8 relating to F.N.B. Corporation Directors
    Compensation Plan (File #333-03495).

6.  Registration Statement on Form S-8 relating to F.N.B. Corporation 401(k)
    Plan (File #333-38372).

7.  Post-Effective Amendment No. 1 on Form S-8 to Registration Statement on Form
    S-4 (File #333-01997).

8.  Post-Effective Amendment No. 1 on Form S-8 to Registration Statement on Form
    S-4 (File #333-22909).

9.  Registration Statement on Form S-3 relating to F.N.B. Corporation
    Subordinated Notes and Daily Cash Accounts (File #333-74737).

10. Registration Statement on Form S-8 relating to stock options assumed in the
    acquisition of Mercantile Bank of Southwest Florida (File #333-42333).

11. Post-Effective Amendment No. 1 on Form S-8 to Registration Statement on Form
    S-4 (File #333-58727).



12. Registration Statement on Form S-3 relating to stock warrants assumed in the
    acquisitions of Southwest Banks, Inc. and West Coast Bancorp, Inc. (File
    #333-31124).

13. Post Effective Amendment No. 1 to Form S-3 relating to the F.N.B.
    Corporation Dividend Reinvestment and Direct Stock Purchase Plan (File
    #333-38374).

14. Amendment No. 1 to Form S-3 relating to the registration of F.N.B.
    Corporation Subordinated Term Notes and Daily Notes (File #333-38370).

15. Registration Statement on Form S-8 relating to the F.N.B. Corporation Salary
    Savings Plan (File #333-40648).

16. Registration Statement on Form S-8 relating to the F.N.B. Corporation 1998
    Directors Stock Option Plan (File #333-38376).

17. Registration Statement on Form S-8 relating to the F.N.B. Corporation 2001
    Incentive Plan (File #333-63042).

18. Registration Statement on Form S-3 relating to the registration of F.N.B.
    Corporation and FNB Capital Trust I common stock, preferred stock, debt
    securities, warrants, and trust preferred securities (File #333-74866).

19. Registration Statement on Form S-8 relating to the F.N.B. Corporation 1996
    Incentive Plan (File #333-83760).

20. Registration Statement on Form S-8 relating to stock option agreements
    granted under the Promistar Financial Corporation 1998 Equity Incentive Plan
    and assumed by F.N.B. Corporation (File #333-83756).

21. Registration Statement on Form S-8 relating to the F.N.B. Corporation 401(k)
    Plan (File #333-97113).

22. Registration Statement on Form S-8 relating to the Roger Bouchard Insurance,
    Inc. 401(k) Plan (File #333-97115).

23. Registration Statement on Form S-3 relating to the F.N.B. Corporation
    Dividend Reinvestment and Direct Stock Purchase Plan (File 333-97111).


                                                       /s/ Ernst & Young LLP


Birmingham, Alabama
May 9, 2003