The street walker was actually an undercover cop.
A television station reports a marked Secret Service Uniformed Division patrol car pulled up to the supposed hooker.
Authorities say a Secret Service sergeant discussed sex acts and agreed to pay 20 bucks.
The uniformed Secret Service officer was busted by D.C. police in the sting operation and charged with solicitation.
The arrested officer's name hasn't been released.
The Secret Service says the officer has been placed on leave while the case is being investigated.