A lorry driver and a pedestrian were killed in separate accidents as the death toll on the country's roads reached four over the bank holiday weekend.
Gardai said a man in his 40s died after being hit by a car on Coolgreany Road in Arklow, Co Wicklow, at about 2.20am on Monday.
The driver was not injured.
In a separate incident on the M1 motorway the driver of an articulated lorry died.
The truck he was driving veered out of control and jack-knifed at about 8.30am near the toll plaza on the southbound carriageway.
The Dublin-bound side of the motorway was closed for several hours following the accident.
Garda forensic collision investigators were examining the scenes of both crashes.
The men's deaths were the third and fourth on roads in the Republic during the June bank holiday weekend.
A man in his 20s died in a car accident near Tourmakeady, Co Mayo, at about 4am on Sunday morning.
It is understood a woman who was also a passenger in the car was critically ill in hospital while the driver suffered serious injuries.
On Saturday, a man in his 40s died when the car he was driving crashed on the M6 motorway near Athlone between the Monksland exit and the slip road for Ballinasloe.