It is being reported that the man who is injured is aged 40 and is from the Sutton/Bayside area of north Dublin.
Witnesses have reported seeing a gang of men attack him with weapons.
Gardaí are investigating a hit-and-run and an alleged assault in Dublin.
Officers said the incident happened on Parnell Street at the junction of Hill Street in Dublin 1 at around 12.20am this morning.
A man in his 40s was found with serious injuries before he was removed by ambulance to The Mater Hospital.
Gardaí believe that the man was hit by a green or blue Audi saloon car which left the scene in the direction of Summerhill.
Witnesses have also said that a number of men got out from this car and assaulted the man.
Gardaí are appealing for witnesses to contact to this incident or anyone with information to them at Mountjoy Garda Station on 01 666 8600.