The robbery took place at 5:05 p.m. Saturday at Zeng's Cent Store on the 7400 block of Stenton Avenue.
Police say the suspect entered the store and pretended to shop.
After several minutes, police say the suspect pulled out a handgun, pointed it at an employee, and demanded money from the cash register.
After the suspect was given an undetermined amount of cash, he fled the store on foot west through an alley of 1300 East Johnson Street.
The suspect is described as a black male, 18 to 22 years-of-age, 5'7-5'8, with a dark complexion. He was wearing a white t-shirt, light colored blue jeans and white sneakers.
Philadelphia police have released surveillance video of the incident.
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.