Exhibit
24
 POWER OF
ATTORNEY
 
 KNOW ALL
PERSONS BY THESE PRESENTS, that each person whose signature appears below
constitutes and appoints Tae Heum Jeong, a true and lawful attorney-in-fact and
agent, with full power to him (including the full power of substitution and
resubstitution), to sign for him or her and in his or her name, place and stead,
in the capacity or capacities set forth below, (1) the Annual Report on Form
10-K for the fiscal year ended December 31, 2008 to be filed by Rexahn
Pharmaceuticals, Inc. (the "Company") with the Securities and Exchange
Commission (the "Commission") pursuant to Section 13 of the Securities Exchange
Act of 1934, as amended, and (2) any amendments to the foregoing Annual Report,
and to file the same, with all exhibits thereto and other documents in
connection therewith, with the Commission, granting unto said attorney-in-fact
and agent, full power and authority to do and perform each and every act and
thing requisite and necessary to be done in connection therewith, as fully to
all intents and purposes as he or she might or could do in person, hereby
ratifying and confirming all that said attorney-in-fact and agent, or his or her
substitute or substitutes, may lawfully do or cause to be done by virtue
hereof.
 
 Signature
                                                                                    
                                                                                    Title
                                                                                    Date/s/ Chang H. Ahn
                                                                                    
                                                                                    Chairman and Chief Executive
      Officer
                                                                                    March 16, 2009Chang H. Ahn/s/ Tae Heum Jeong
                                                                                    
                                                                                    Chief Financial Officer, Secretary and
      Director
                                                                                    March 16, 2009Tae Heum Jeong/s/ Freddie Ann Hoffman
                                                                                    
                                                                                    Director
                                                                                    March 16, 2009Freddie Ann Hoffman/s/David McIntosh
                                                                                    
                                                                                    Director
                                                                                    March 16, 2009David McIntosh/s/ Charles Beever
                                                                                    
                                                                                    Director
                                                                                    March 16, 2009Charles Beever/s/ Kwang Soo Cheong
                                                                                    
                                                                                    Director
                                                                                    March 16, 2009Kwang Soo Cheong/s/ Y. Michele Kang
                                                                                    
                                                                                    Director
                                                                                    March 16, 2009Y. Michele Kang