Officers were called to the house in Willowbrook Park, Celbridge, at about 20:50 local time on Tuesday.
The man, who was in his 30s, was pronounced dead shortly before 22:30.
A man in his 20s was arrested at the scene and has been taken to Leixlip Garda (police) station for questioning.
The body remains at the house, which has been cordoned off pending the arrival of the deputy state pathologist.
Police have made an arrest after the death of a man who was found with head injuries at a house in County Kildare.