It happened around 7:45 pm on Monday near Highway 140.
When police arrived at the gas station, they found a 53-year-old victim with a head injury.
Investigators say the 53-year-old had been hit in the head with a metal pipe.
The victim was taken to a hospital. Their condition was not released.
Police shared a photo of the suspect captured from the store's surveillance footage. Officials say the suspect was wearing a dark-colored baseball cap, light blue jeans, a green patterned shirt.
Anyone with information is asked to call the Merced Police Department.