It happened at the Cricket Wireless store on the 4500 block of North Broad Street just before 5 p.m.
The suspect entered the store armed with a handgun and approached the counter.
He threatened an employee and demanded money.
The robber got away with $265 in cash before fleeing north on Broad Street.
Police describe the suspect as a black male, 5'3" tall with a medium build and complexion. He was wearing a blue puffy jacket, dark colored gloves, cuffed blue jeans, a dark ski mask, black sneakers with white on the back and was armed with a handgun.
Anyone with information on this robbery should contact police at 215.686.TIPS (8477) or text a tip to PPD TIP (773847).
VIDEO: Click here to watch the surveillance video