<PAGE>
 
                                                                    EXHIBIT 11.2

                        NEWBRIDGE NETWORKS CORPORATION

                       COMPUTATION OF EARNINGS PER SHARE

        (Accounting principles generally accepted in the United States)
        (Canadian dollars, amounts in thousands except per share data)
                                  (Unaudited)

<TABLE> 
<CAPTION> 
                                                          Fiscal quarter ended             Three fiscal quarters ended        
                                                      ---------------------------          ---------------------------       
                                                       Feb 1,             Jan 26,           Feb 1,             Jan 26,    
                                                        1998               1997              1998               1997      
                                                        ----               ----              ----               ----      
<S>                                                   <C>                <C>               <C>               <C>          
Net earnings(loss) (U.S. GAAP)                                                              
                                                                                                                         
 Net earnings (loss), as reported, Cdn GAAP           $(144,283)         $ 63,031          $(21,936)         $186,613    
                                                                                                                         
 Write off of purchased research and development        
   in process                                           (52,762)          (96,940)          (52,762)          (96,940)   
                                                                                                                         
 Amortization of purchased research and 
   development in process, Cdn GAAP                      26,381                --            26,381                --    
                                                      ---------          --------          --------          --------    
                                                                                                                         
 Net earnings (loss), U.S. GAAP                       $(170,664)         $(33,909)         $(48,317)         $ 89,673    
                                                      =========          ========          ========          ========     
                                                                                                       
Earnings (loss) per share (U.S. GAAP) - Basic                                                          
                                                                                                       
 Net earnings (loss)                                  $(170,664)         $(33,909)         $(48,317)         $ 89,673    
                                                      =========          ========          ========          ========    

 Weighted average number of Common Shares 
   outstanding during the period                        175,376           170,941           174,338           170,140    
                                                      =========          ========          ========          ========    
                                                                                                                         
 Earnings (loss) per share (U.S. GAAP)                      (97)c             (20)c             (28)c              53c       
                                                      ---------          --------          --------          --------

Earnings (loss) per share (U.S. GAAP) - Diluted
 
 Net earnings (loss)                                  $(170,664)         $(33,909)         $(48,317)         $ 89,673
                                                      =========          ========          ========          ========     

 Weighted average number of Common Shares 
   outstanding during the period                        175,376           170,941           174,338           170,140
 
 Net effect of dilutive stock options
   based on the treasury stock method                        --                --                --             4,667
                                                      ---------          --------          --------          --------
 
 Weighted average number of Common Shares 
   and equivalents outstanding 
   during the period                                    175,376           170,941           174,338           174,807
                                                      =========          ========          ========          ========    

 Earnings (loss) per share (U.S. GAAP)                      (97)c             (20)c             (28)c              51c       
                                                      =========          ========          ========          ========    
 
Earnings (loss) per share expressed in U.S. Dollars
 
 Daily average exchange rate of a Canadian
   dollar for U.S. dollars as reported by the
   Federal Reserve Bank of New York                   $  0.7006          $ 0.7406          $ 0.7071          $ 0.7346
 
 Earnings (loss) per share (U.S. GAAP)
   - Basic, in U.S. dollars                                 (68)c             (15)c             (20)c              39c      
                                                      =========          ========          ========          ========    
 Earnings (loss) per share (U.S. GAAP)
   - Diluted, in U.S. dollars                               (68)c             (15)c             (20)c              38c        
                                                      =========          ========          ========          ========    
</TABLE>