A man in his forties died this morning when his truck left the road in Co Monaghan and hit a tree.
Gardaí are investigating the crash, which took place at around 8.15 a.m. on the Monaghan/Roslea road at Kincorragh, Smithboro.
There was no other vehicle involved.
The body of the man, who died at the scene, was taken to Cavan General hospital where a post-mortem will be carried out.
Elsewhere, a man (32) died when his motorcycle crashed at Kilooley, Gortnahoe, Co Tipperary, at 4.30 p.m. yesterday. He has not yet been named.
Today's death brings to four the number of people killed on the roads over the Bank Holiday weekend.
A male pedestrian in his 60s died after being hit by a car in Co Tipperary on Saturday, while a 91-year-old woman was killed in a car crash in Co Cork on Sunday.
During the equivalent period last year, 13 people died and at least seven were seriously injured.