The man in his 50s, died from his injuries at the scene.
Emergency services were called to the crash involving a pedestrian and a car on the R446 at Marshbrook, along the Westmeath/Offaly border, shortly before 2 o'clock this morning.
The pedestrian, a man in his 50s, died from his injuries at the scene.
The occupants of the car received medical attention, but were not seriously injured.
The road is currently closed, and the scene has been preserved for a technical examination.
Local diversions are in place.
Gardaí are appealing to anyone who was travelling between Moate and Horseleap at the time, especially those with dashcam footage to come forward.