It happened at 4:52 p.m. Saturday at the store located at 101 East Olney Avenue.
Police say the suspect entered the store, armed with a handgun, and demanded money.
Surveillance video released by police shows the suspect pointing a handgun at the clerk while making the demands.
The worker opens the cash register and the suspect leans over, grabs the cash, the forces the employee to the rear of the store.
The bandit then flees on foot in an unknown direction.
The suspect is described as a black male, about 20 y ears old, medium complexion, with a beard with a stocky build. He was wearing a red and black baseball hat with a Cincinnati Reds logo, black hooded sweatshirt and blue jeans.
Anyone with information is asked to contact Philadelphia Police at 215-686-TIPS (8477), text a tip to PPD TIP (773847) or through PhillyPolice.com.