The suspect is described as a black male, 6', 160 to 170 pounds, 35 to 45 years of age, with a thin build and a dark goatee.
The shooting happened around 4:50 p.m. at the Shell station in the 2500 block of Newport Gap Pike in the Cranston Heights section.
Police say a man approached and asked to buy something located behind the counter.
The employee turned his back to grab the item but, when he turned around, he found the suspect pointing a gun.
Investigators say the suspect demanded money, and then shot the worker in the stomach.
Still, the victim was able to open the cash register. The gunman grabbed money and ran from the store.
The suspect left in a dark colored SUV with a missing grill, heading southbound on Newport Gap Pike. Police released surveillance images of the vehicle on Saturday.
The victim, a 47-year-old man, was take to the hospital with non-life-threatening injuries.
Anyone with information is asked to contact Detective Jonathon Packard at Troop 2, Glasgow, at 302-365-8434.