<PAGE>

                                                                      EXHIBIT 11


                       Alabama National BanCorporation
                  Computation of Earnings Per Share (Unaudited)
                    (In thousands, except per share amounts)

<TABLE>
<CAPTION>
                                                                                                     Per Share
                                                            Income               Shares                Amount
<S>                                                      <C>                   <C>                  <C>
THREE MONTHS ENDED SEPTEMBER 30, 1999
Basic EPS net income ............................          $ 5,720                11,127               $   0.51
                                                                                                       ========
Effect of dilutive securities options ...........               --                   188
                                                           -------                ------
Diluted EPS .....................................          $ 5,720                11,315               $   0.51
                                                           =======                ======               ========

THREE MONTHS ENDED SEPTEMBER 30, 1998
Basic EPS net income ............................          $ 5,052                10,861               $   0.47
                                                                                                       ========
Effect of dilutive securities options ...........               --                   300
                                                           -------                ------
Diluted EPS .....................................          $ 5,052                11,161               $   0.45
                                                           =======                ======               ========

NINE MONTHS ENDED SEPTEMBER 30, 1999
Basic EPS net income ............................          $16,119                11,084               $   1.45
                                                                                                       ========
Effect of dilutive securities options ...........               --                   189
                                                           -------                ------
Diluted EPS .....................................          $16,119                11,273               $   1.43
                                                           =======                ======               ========

NINE MONTHS ENDED SEPTEMBER 30, 1998
Basic EPS net income ............................          $14,351                10,722               $   1.34
                                                                                                       ========
Effect of dilutive securities options ...........               --                   356
                                                           -------                ------
Diluted EPS .....................................          $14,351                11,078               $   1.30
                                                           =======                ======               ========
</TABLE>

                                       1