It happened at the 7-11 on the 2900 block of South 70th Street in Southwest Philadelphia around 1:00 Wednesday morning.
Police say the suspect demanded cash, then hit the clerk in the face with a gun.
The suspect grabbed some cash from register and then ran off.
The clerk was taken to The Hospital of the University of Pennsylvania with injuries to his face.
Police are reviewing surveillance video to try to identify the suspect.
