The incident happened at 10:40 a m. at the store located at 150 East Champlost Street.
Police say the suspect approached the counter and pointed a handgun at the clerk, demanding money and cigarettes.
The clerk then removed the cash register drawers and placed them on the counter.
The robber got away with $250 in cash and several packs of cigarettes totaling $350.
He fled the store on foot in an unknown direction.
Police describe the suspect as a black male, 5'9" tall with a light complexion and thin build. He was wearing an olive green hooded jacket, blue jeans, dark colored mask covering his nose and mouth, and blue latex gloves.
If you see this suspect do not approach him, contact 911 immediately.
Anyone with information should call police at 215.686.TIPS (8477) or text a tip to PPD TIP (773847).