EXHIBIT 21.1

SUBSIDIARIES OF MERCURY INTERACTIVE CORPORATION



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|------------------------------------------------------------ |  | ----------------------------
|Subsidiary Legal Name                                        |  | JURISDICTION OFINCORPORATION
|                                                             | 
|Mercury Interactive Austria GesmbH                           |  | Austria                     
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|Mercury Interactive Brasil Ltda.1                            |  | Brazil                      
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|Mercury Interactive Canada, Inc.                             |  | Canada                      
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|Mercury Interactive A/S                                      |  | Denmark                     
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|Mercury Interactive Oy                                       |  | Finland                     
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|Mercury Interactive France2                                  |  | France                      
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|Mercury Interactive (Hong Kong) Ltd.3                        |  | Hong Kong                   
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|Mercury Interactive (HK) Ltd. Beijing                        |  | Beijing                     
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|Mercury Interactive Sales and Service India Private Limited4 |  | India                       
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|Mercury Interactive (Israel) Ltd.                            |  | Israel                      
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|Mercury Interactive (Australia) Pty. Limited5                |  | Australia                   
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|Mercury Interactive S.r.L (Italy)6                           |  | Italy                       
|                                                             | 
|Mercury Interactive Japan KK                                 |  | Japan                       
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|Mercury Interactive Luxembourg SA7                           |  | Luxembourg                  
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|Mercury Interactive Mexico S. de R.L. de C.V.8               |  | Mexico                      
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|Mercury Interactive (Europe) B.V.                            |  | Netherlands                 
|                                                             | 
|Mercury Interactive GmbH                                     |  | Germany                     
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|Mercury Interactive (UK) Limited                             |  | UK                          
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|Mercury Interactive B.V.                                     |  | Netherlands                 
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|Mercury Interactive Poland Sp z oo                           |  | Poland                      
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|Mercury Interactive (Singapore) Pte. Ltd.                    |  | Singapore                   
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|Mercury Interactive (Shanghai) Company Ltd.                  |  | China                       
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|Mercury Interactive India Liaison Office                     |  | India                       
|                                                             | 
|Mercury Interactive SA (Pty) Limited                         |  | South Africa                
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|Mercury Interactive (Korea) Co. Ltd.                         |  | South Korea                 
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|Mercury Interactive, S.L. Unipersonal                        |  | Spain                       
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|Mercury Interactive Nordic AB                                |  | Sweden                      
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|Mercury Interactive (Switzerland) GmbH                       |  | Switzerland                 
|                                                             | 
|Mercury Interactive Freshwater, Inc.                         |  | Delaware                    
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|Mercury Interactive Government Solutions, Inc.               |  | Delaware                    
|                                                             | 
|Mercury Interactive Partners LLC                             |  | Delaware                    
|                                                             | 
|Mercury Interactive Ventures LP9                             |  | Delaware                    
|                                                             | 
|Double B Acquisition Corp.                                   |  | Delaware                    
|                                                             | 
|ClickCadence, LLC                                            |  | Pennsylvania                
|                                                             | 
|Kanga Acquisition LLC                                        |  | Delaware                    
|                                                             | 
|Kintana SARL                                                 |  | France                      
|                                                             | 
|Kintana GmbH                                                 |  | Germany                     
|                                                             | 
|Kintana Limited                                              |  | UK                          



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|                        |  |                             
|----------------------- |  | ----------------------------
|SUBSIDIARY LEGAL NAME   |  | JURISDICTION OFINCORPORATION
|                        | 
|Performant, Inc.        |  | Delaware                    
|                        | 
|Systinet Corporation    |  | Delaware                    
|                        | 
|Systinet S.R.O.         |  | Czechoslovakia              
|                        | 
|Systinet SAS            |  | France                      
|                        | 
|Systinet Nederland B.V. |  | Netherlands                 
|                        | 
|Tefensoft Inc.          |  | Delaware                    
|                        | 
|Tefensoft Ltd.          |  | Israel                      

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|(1) | 99% interest owned by Mercury Interactive Corporation and 1% interest owned by Mercury Interactive Canada, Inc.
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|(2) | 81% interest owned by Mercury Interactive Corporation and 19% interest owned by Mercury Interactive (Europe) B.V.
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|(3) | 99% interest owned by Mercury Interactive Corporation and 1% interest owned by Mercury Interactive B.V.
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|(4) | 99% interest owned by Mercury Interactive Corporation and 1% interest owned by Mercury Interactive (Singapore) Pte. Ltd.
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|(5) | 50% interest owned by Mercury Interactive Corporation and 50% interest owned by Mercury Interactive (Israel) Limited
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|(6) | 95% interest owned by Mercury Interactive Corporation and 5% interest owned by Mercury Interactive B.V.
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|(7) | 75% interest owned by Mercury Interactive Corporation and 25% interest owned by Mercury Interactive B.V.
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|(8) | 99% interest owned by Mercury Interactive Corporation and 1% interest owned by Mercury Interactive Freshwater, Inc.
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|(9) | 99% interested owned by limited partner Mercury Interactive Corporation and 1% interest owned by general partner Mercury Interactive Partners LLC
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