Exhibit 12.1

CERTIFICATION OF THE CHIEF
EXECUTIVE OFFICER 
PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I,
Jacob (Yanki) Margalit, certify that:

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|1. | I have reviewed this
  annual report on Form 20-F of Aladdin Knowledge Systems Ltd. (the Company);                                                                                                                                                                                                                                       
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|2. | Based on my knowledge,
  this report does not contain any untrue statement of a material fact or omit
  to state a material fact necessary to make the statements made, in light of
  the circumstances under which such statements were made, not misleading with
  respect to the period covered by this report;                         
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|3. | Based on my knowledge, the
  financial statements, and other financial information included in this
  report, fairly present in all material respects the financial condition,
  results of operations and cash flows of the company as of, and for, the
  periods presented in this report;                                               
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|4. | The Companys other
  certifying officer(s) and I are responsible for establishing and maintaining
  disclosure controls and procedures (as defined in Exchange Act Rules
  13a-15(e) and 15d-15(e)) and internal control over financial reporting (as
  defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the Company and
  have:
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|   | (a)                                                                                                                                                                                                                                                                                                                                         | designed such disclosure controls and procedures, or
  caused such disclosure controls and procedures to be designed under our
  supervision, to ensure that material information relating to the Company,
  including its consolidated subsidiaries, is made known to us by others within
  those entities, particularly during the period in which this report is being
  prepared;
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|   | (b)                                                                                                                                                                                                                                                                                                                                         | designed such internal control over financial
  reporting, or caused such internal control over financial reporting to be
  designed under our supervision, to provide reasonable assurance regarding the
  reliability of financial reporting and the preparation of financial
  statements for external purposes in accordance with generally accepted
  accounting principles;    
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|   | (c)                                                                                                                                                                                                                                                                                                                                         | evaluated the effectiveness of the Companys
  disclosure controls and procedures and presented in this report our
  conclusions about the effectiveness of the disclosure controls and
  procedures, as of the end of the period covered by this report based on such
  evaluation; and                                                                                             
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|   | (d)                                                                                                                                                                                                                                                                                                                                         | disclosed in this report any change in the Companys
  internal control over financial reporting that occurred during the period
  covered by the annual report that has materially affected, or is reasonably
  likely to materially affect, the Companys internal control over financial
  reporting; and                                                                         
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|5. | The Companys other
  certifying officer(s) and I have disclosed, based on our most recent
  evaluation of internal control over financial reporting, to the Companys
  auditors and the audit committee of the Companys board of directors (or
  persons performing the equivalent functions):                                          

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| | (a) | All significant deficiencies and material weaknesses
  in the design or operation of internal control over financial reporting which
  are reasonably likely to adversely affect the Companys ability to record,
  process, summarize and report financial information; and
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| | (b) | Any fraud, whether or not material, that involves
  management or other employees who have a significant role in the Companys
  internal control over financial reporting.                                                                                                 

Date:
July 2, 2007

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| | By /s/ Jacob (Yanki)
  Margalit
| |                                 | 
| | Jacob (Yanki) Margalit         
| | Chief Executive Officer        
| | (Principal Executive
  Officer)

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