The robbery happened at 4:30 p.m. Saturday at Toll Gate Liquors in the 3000 block of Lancaster Avenue.
According to investigators, the suspect entered the store and pointed a gun at the clerk, ordering him to hand over the money from the register.
The man fled after obtaining an unknown amount of cash.
The suspect is described as a black male, standing 5'7" tall with short, dark hair and a large build. He was wearing a blue rugby-style long-sleeve shirt and had a gold ring on his left hand.
Anyone with information can call the Wilmington Police Confidential Tip Line at 302.576.3990 or Crime Stoppers at 1-800.TIP.3333.