Exhibit 31(A)

                               CERTIFICATIONS


I, William P. Heath, Jr., certify that:

1.     I have reviewed this annual report on Form 10-K of FNB Corporation;

2.     Based on my knowledge, this report does not contain any untrue
       statement of a material fact or omit to state a material fact
       necessary to make the statements made, in light of the circumstances
       under which such statements were made, not misleading with respect to
       the period covered by this report;

3.     Based on my knowledge, the financial statements, and other financial
       information included in this report, fairly present in all material
       respects the financial condition, results of operations and cash flows
       of the registrant as of, and for, the periods presented in this
       report;

4.     The registrant's other certifying officer and I are responsible for
       establishing and maintaining disclosure controls and procedures (as
       defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal
       control over financial reporting (as defined in Exchange Act Rules
       13a-15(f) and 15d-15(f)) for the registrant and have:

       (a)   Designed such disclosure controls and procedures, or caused such
             disclosure controls and procedures to be designed under our
             supervision, to ensure that material information relating to the
             registrant, including its consolidated subsidiaries, is made
             known to us by others within those entities, particularly during
             the period in which this report is being prepared;

       (b)   Designed such internal control over financial reporting, or
             caused such internal control over financial reporting to be
             designed under our supervision, 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;

       (c)   Evaluated the effectiveness of the registrant's disclosure
             controls and procedures and presented in this report our
             conclusions about the effectiveness of the disclosure controls
             and procedures, as of the end of the period covered by this
             report based on such evaluation; and

       (d)   Disclosed in this report any change in the registrant's internal
             control over financial reporting that occurred during the
             registrant's most recent fiscal quarter (the registrant's fourth
             fiscal quarter in the case of an annual report) that has
             materially affected, or is reasonably likely to materially
             affect, the registrant's internal control over financial
             reporting; and
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5.     The registrant's other certifying officer and I have disclosed, based
       on our most recent evaluation of internal control over financial
       reporting, to the registrant's auditors and the audit committee of the
       registrant's board of directors (or persons performing the equivalent
       functions):

       (a)   All significant deficiencies and material weaknesses in the
             design or operation of internal control over financial reporting
             which are reasonably likely to adversely affect the registrant's
             ability to record, process, summarize and report financial
             information; and

       (b)   Any fraud, whether or not material, that involves management or
             other employees who have a significant role in the registrant's
             internal control over financial reporting.


Date:   March 10, 2006                 /s/William P. Heath, Jr.
                                          William P. Heath, Jr.
                                          President & Chief Executive Officer
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