It happened just after 9:45 p.m. at the store on Dairy and Bell Avenues.
Investigators say two men were shot in front of one of the pumps and were taken to local hospitals with non-life threatening injuries.
Police say the suspect ran away, but they have not released a possible description.
Officers found shell casings at the scene, and they are reviewing surveillance footage from the store to help identify the suspect.
The motive for the shooting is unknown.