
<PAGE>
 
                                                                    EXHIBIT 11.1



                               ADAC LABORATORIES
                      COMPUTATION OF NET INCOME PER SHARE
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
                                  (UNAUDITED)


<TABLE> 
<CAPTION> 
                                     Three Months Ended                  Six Months Ended
                                     ------------------                  ----------------

                                  March 31,         April 2,          March 31,       April 2,
                                    1996              1995              1996            1995
                                    ----              ----              ----            ----
<S>                               <C>               <C>               <C>             <C>                                          
Average shares outstanding         17,271            16,140            17,166          15,555
                                                                                   
Net effect of dilutive stock                                                       
   options and warrants             1,000               497               824           1,111
                                ---------         ---------         ---------       ---------
Average common and common                                                          
 equivalent shares                                                                 
 outstanding                       18,271            16,637            17,990          16,666
                                =========         =========         =========       =========

Net income                        $ 3,938           $ 2,754           $ 7,479          $5,184
                                =========         =========         =========       =========
Net income per share              $  0.22           $  0.17           $  0.42           $0.31
                                =========         =========         =========       ========-   
</TABLE> 
