<PAGE>
 
                                  EXHIBIT 11
                                  ----------

                          STATEMENT RE COMPUTATION OF
                          ---------------------------

                              PER SHARE EARNINGS
                              ------------------

                                      12
<PAGE>
 
                                                                      Exhibit 11
                                                                      ----------



                            LIFE TECHNOLOGIES, INC.
            STATEMENT RE COMPUTATION OF PRIMARY PER SHARE EARNINGS
            ------------------------------------------------------
                      for the three and nine months ended
                          September 30, 1997 and 1996
                 (amounts in thousands, except per share data)
<TABLE> 
<CAPTION> 
                                    Three months ended     Nine months ended
                                       September 30,         September 30,
                                    -------------------    ------------------
                                     1997         1996       1997       1996
                                    -------     -------    -------    ------- 
<S>                                 <C>         <C>        <C>        <C>
Net income                          $ 7,873     $ 6,631    $24,049    $21,608
                                    =======     =======    =======    =======
                                                                   
Weighted average shares                                            
  outstanding                        23,243      22,905     23,122     22,857
                                                                   
Weighted average effect of                                         
  common stock equivalents              727         669        760        588
                                    -------     -------    -------    -------
                                                                   
                                     23,970      23,574     23,882     23,445
                                    =======     =======    =======    =======
                                                                   
Primary net income per share        $  0.33     $  0.28    $  1.01    $  0.92
                                    =======     =======    =======    =======
</TABLE> 
                             

                                      13
<PAGE>
 
                                                                     Exhibit 11
                                                                     ----------

 
                            LIFE TECHNOLOGIES, INC.
         STATEMENT RE COMPUTATION OF FULLY DILUTED PER SHARE EARNINGS
         ------------------------------------------------------------
                      for the three and nine months ended
                          September 30, 1997 and 1996
                 (amounts in thousands, except per share data)
<TABLE> 
<CAPTION> 
                                 Three months ended    Nine months ended
                                     September 30,        September 30,
                                 -------------------   ------------------
                                  1997         1996     1997        1996
                                 -------     -------   -------    -------
<S>                              <C>         <C>       <C>        <C>
Net income                       $ 7,873     $ 6,631   $24,049    $21,608
                                 =======     =======   =======    =======
                                                               
Weighted average shares                                        
  outstanding                     23,243      22,905    23,122     22,857
                                                               
Weighted average effect of                                     
  common stock equivalents           798         729       877        750
                                 -------     -------   -------    -------
                                                               
                                  24,041      23,634    23,999     23,607
                                 =======     =======   =======    =======
                                                               
Fully diluted net income                                       
per share                        $  0.33     $  0.28   $  1.00    $  0.92
                                 =======     =======   =======    =======
                                                               
Primary net income per share     $  0.33     $  0.28   $  1.01    $  0.92
                                 =======     =======   =======    =======
</TABLE> 

                                      14