The incident took place around 8am on Saturday morning.
Gardaí are investigating a fatal single vehicle road traffic collision that occurred on the M9 southbound just after Junction 10, Knocktopher, on Saturday 13 Juny at approximately 8am.
A man, aged in his 40s, was pronounced dead at the scene and his body has been removed to University Hospital Waterford.
The road remains closed southbound currently and local diversions are in place.
The scene is due to be examined by Garda Forensic Investigators.
Gardaí are appealing for anyone who may have information, or any motorists who may have been travelling on the M9 near Junction 10 at the time of the collision, to contact Gardaí in Thomastown on 056 775 4150 or the Garda Confidential Line on 1800 666 111.
