<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)
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                                                              Fiscal quarter ended
                                                            -------------------------
                                                             Aug 3,           Jul 28,
                                                              1997             1996
                                                            --------         --------  
<S>                                                         <C>              <C> 
EARNINGS PER SHARE (U.S. GAAP) - PRIMARY                               
                                                                       
    Net earnings                                            $ 64,354         $ 60,801
                                                            ========         ========
    Weighted average number of Common Shares                           
       outstanding during the period                         172,964          169,228
                                                                       
    Net effect of dilutive stock options                               
       based on the treasury stock method                      6,857            5,702
                                                            --------         --------  
    Weighted average number of Common                                  
       Shares and equivalents outstanding                              
       during  the period                                    179,821          174,930
                                                            ========         ========
    Earnings per share (U.S. GAAP)                          $   0.36         $   0.35
                                                            ========         ========

EARNINGS PER SHARE (U.S. GAAP) - FULLY DILUTED                         
                                                                       
    Net earnings                                            $ 64,354         $ 60,801
                                                            ========         ========
    Weighted average number of Common Shares                           
       outstanding during the period                         172,964          169,228
                                                                       
    Net effect of dilutive stock options                               
       based on the treasury stock method                      8,305            5,702
                                                            --------         --------  
                                                                       
    Weighted average number of Common                                  
       Shares and equivalents outstanding                              
       during the period                                     181,269          174,930
                                                            ========         ========
                                                                       
    Earnings per share (U.S. GAAP)                          $   0.36         $   0.35    
                                                            ========         ========
                                                                       
EARNINGS 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                     $ 0.7242         $ 0.7309
                                                                       
    Earnings per share (U.S. GAAP)                                     
        - Primary, in U.S. dollars                          $   0.26         $   0.25    
                                                            ========         ========
                                                                       
    Earnings per share (U.S. GAAP)                                     
        - Fully diluted, in U.S. dollars                    $   0.26         $   0.25   
                                                            ========         ========
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