EXHIBIT 31.1

CERTIFICATION PURSUANT TO RULE 13a-14(a) OR RULE 15d-14(a)

I, David T. Hung, M.D., certify that:

1. I have reviewed this annual report on Form 10-KSB of Medivation, Inc.;

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 small business issuer as of, and for, the periods presented in this
report;

4. The small business issuer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 small business issuer 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 small business issuer, 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) 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;

c) Evaluated the effectiveness of the small business issuer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 small business issuers internal control over financial reporting that occurred during
the small business issuers most recent fiscal quarter (the small business issuers fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the small business
issuers internal control over financial reporting; and

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

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 small business issuer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 small business
issuers internal control over financial reporting.

Date: February 19, 2008



|       |  |                                      
|------ |  | -------------------------------------
|       |  | /s/ DAVID T. HUNG , M.D.             
|Name:  |  | David T. Hung, M.D.                  
|Title: |  | President and Chief Executive Officer