Update - 12.55pm: The dead man was a Polish native who had been living in the Fermoy area.
He and another man, not known to the deceased, were attacked by two others at the filling station on Pike Road Fermoy shortly after 10.30pm.
The Evening Echo report that the men were armed with iron bars. It is understood that gardaí recovered an iron bar this morning, thought to have been used in the attack.
The dead man, who was pronounced dead at the scene, is believed to be a 40-year-old who had lived in the area for a number of years.
The garage where the incident occurred is one of the busiest in the county. There were up to 20 truckers parked at the garage when the incident occurred.
All four men involved in the incident are believed to be from Eastern Europe.
Gardaí are appealing for witnesses, in particular any persons who were in the vicinity of Pyke Road/Dublin Road between 8.30pm and 10.30pm last night.
They have asked witnesses to contact the incident room at Fermoy Garda Station on 025 - 82100, the Garda Confidential Line 1 800 666 111 or any Garda Station.
Update 8.35am:A man has died and a second is in hospital following an assault at a filling station near Fermoy in County Cork last night.
It is understood that the man, who is aged 40 and is believed to be a Polish national, died after being attacked by another man with a baseball bat.
A second man was taken to Cork University Hospital where his injuries are described as non-life-threatening.
Several of the truck drivers who had been sleeping at the time, said they heard noises and shouts before raising the alarm.
A staff member from the filling station came, saw the body on the ground and called the Gardaí.
It is thought the man who died and the injured man had been living in Cork for some time.
Gardaí have arrested two men in their early 40s and late 20s as part of the investigation.
They are being held at Fermoy and Mallow Garda Stations under Section 4 of the Criminal Justice Act, 1984.
Earlier: Fermoy gardaí are treating as suspicious the death of a man whose body was found at a truck parking area of of a filling station on the Dublin Road in the town last night.
It is understood the victim sustained serious head injuries during a fight involving up to three men.
The row broke out at the Amber fuel station on the edge of the town at around 10.30pm last night.
It is reported by Red FM's Lana O'Connor that the man was pronounced dead at the scene and the services of the State Pathologist's office have been requested by Gardaí.
The area has been sealed off this morning pending the arrival of crime scene investigators.