It happened at the Lukoil on the 1900 block of North Broad Street at 9:40 a.m.
Video shows the armed robber grabbing cash from the register and ordering the employee to give him packs of cigarettes.
No one was injured.
Police say the suspect is a black man, 5'8, tall, with a thin build. He was wearing a gray hooded sweat jacket and a gray and white cloth over his face.
