The collision happened on the Brideswell to Athlone Road at around 4.00am
Five people have been hospitalised after a two-car road traffic collision in Co Roscommon.
Gardaí are investigating the collision on the Brideswell to Athlone Road at around 4.00am this morning.
The sole occupant of one car, a 23-year-old man was seriously injured and has been taken to Tullamore Hospital.
There were two adults and two children - aged two and six years - in the second car.
All four were taken to Portiuncula Hospital in Ballinasloe for treatment. Their medical condition is unknown.
The road is closed to facilitate a forensic collision examination, and the road will remain closed until lunchtime.
There are also local diversions in place.
Witnesses to the collision are asked to contact Roscommon garda station on 090-6638-300, the Garda Confidential Line at 1800-666-111 or any garda station.