Exhibit 21

Subsidiaries of VASCO Data Security International, Inc.



|                                                                                                                                                                      |  |                                                                 
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------- |  | ----------------------------------------------------------------
|Name of Subsidiary                                                                                                                                                    |  | State or Country of Incorporation                               
|VASCO Data Security, Inc.                                                                                                                                             |  | Delaware, U.S.A.                                                
|VASCO Data Security Europe NV/SA                                                                                                                                      |  | Belgium                                                         
|VASCO Data Security NV/SA                                                                                                                                             |  | Belgium                                                         
|Lintel Security NV/SA                                                                                                                                                 |  | Belgium                                                         
|VASCO Data Security Asia-Pacific Pte. Ltd                                                                                                                             |  | Singapore                                                       
|VASCO Data Security Pty Ltd                                                                                                                                           |  | Australia                                                       
|VASCO Data Security Australia Pty Ltd                                                                                                                                 |  | Australia                                                       
|VASCO Data Security B.V.                                                                                                                                              |  | The Netherlands                                                 
|VASCO Data Security Austria GmbH                                                                                                                                      |  | Austria                                                         
|Able NV                                                                                                                                                               |  | Belgium                                                         
|Able Holding BVBA                                                                                                                                                     |  | Belgium                                                         
|VASCO Data Security International, GmbH                                                                                                                               |  | Switzerland                                                     
|VASCO Data Security Solutions, GmbH                                                                                                                                   |  | Switzerland                                                     
|VASCO Segurança de Dados Brasil Ltda.                                                                                                                                 |  | Brazil                                                          
|Kabushiki Kaisha VASCO Data Security Japan                                                                                                                            |  | Japan                                                           
|VASCO Data Security Private (India) Limited                                                                                                                           |  | India                                                           
|VASCO Data Security Middle East SPC                                                                                                                                   |  | Bahrain                                                         
|VASCO Data Security UK Limited                                                                                                                                        |  | United Kingdom                                                  
|VASCO Data Security France SAS
VASCO Software (Beijing) Co. Ltd. - FICE
DigiNotar B.V (effective January 1, 2011)
DigiNotar Notariaat B.V.(effective January 1, 2011) |  | France Peoples Republic of China The Netherlands
The Netherlands