Two other men are seriously injured.
The single-vehicle crash happened in Trafrask, Adrigole at about 6.10 yesterday evening.
The car left the road and went into a ditch, and three men in their 30s were seriously injured.
They were taken to Cork University Hospital, and one man is now in a critical condition.
Garda forensics are en route to the scene to carry out an examination.
The road is currently open, but it will be closed for a short time for a forensic exam.
