35-year-old man Paddy Kelly, from Castleblayney, Co. Monaghan, has not been seen since Monday evening.
He is described as 1.83m (6ft) in height, slight build, blue eyes and brown hair.
It is understood that Paddy is driving a silver/blue Toyota Auris, reg 09 MN 6569.
Anyone with information regarding his whereabouts is asked to contact Castleblayney Garda station on 042 9740668.