**Exhibit
      12.1**




**CERTIFICATION
      PURSUANT TO**


**SECTION
      302(a) OF THE SARBANES-OXLEY ACT OF 2002**




I,
      Geoffrey P. Kempler, certify that:




1.
            I
                have reviewed this annual report on Form 20-F of Prana Biotechnology
                Limited;




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;




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
                registrant as of, and for, the periods presented in this
                report;




4.
            The
                registrant’s other certifying officer 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)) for the registrant
                and have:




(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 registrant, 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;




(b)
      [Paragraph omitted pursuant to SEC Release Nos. 33-8238 and
      34-47986]




(c)
      Evaluated the effectiveness of the registrant’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




(d)
      Disclosed in this report any change in the registrant’s internal control over
      financial reporting that occurred during the registrant’s most recent fiscal
      quarter (the registrant’s fourth fiscal quarter in the case of an annual report)
      that has materially affected, or is reasonably likely to materially affect,
      the
      registrant’s internal control over financial reporting; and




5.
            The
                registrant’s other certifying officer and I have disclosed, based on our
                most recent evaluation of internal control over financial reporting,
                to
                the registrant’s auditors and the audit committee of the registrant’s
                board of directors (or persons performing the equivalent
                function):




(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 registrant’s ability to record, process, summarize and
      report financial information; and




(b)
      Any
      fraud, whether or not material, that involves management or other employees
      who
      have a significant role in the registrant’s internal control over financial
      reporting.




Date:
      September 29, 2006






/s/
      Geoffrey P. Kempler *


Geoffrey
      P. Kempler


Chief
      Executive Officer




*  The
      originally executed copy of this Certification will be maintained at the
      Registrant’s offices and will be made available for inspection upon
      request.