Exhibit 31.1
I, Chang H. Ahn, certify that:

I have reviewed this Amendment No. 1 to the annual report on Form 10-K of Rexahn Pharmaceuticals, Inc. and
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;

Date: March 24, 2009 
/s/ Chang H. Ahn
Chang H. Ahn
Chief Executive Officer