It happened at a house in the Longfield Way area of Ballyhalbert, Co Down.
Police say that at around 11.00 pm a number of masked men forced their way into the house and assaulted one of the male occupants with hammers.
He was taken to hospital for treatment to his injuries which are not believed to be life threatening at this stage.
A second male who was in the house was not injured during this incident.
Detective Sergeant Niall Bell would appeal to anyone who noticed anyone acting suspiciously in the area to contact Detectives at Criminal Investigation Branch on the non-emergency number 101, quoting reference 1525 17/09/17.
Alternatively, if someone would prefer to provide information without giving their details they can contact the independent charity Crimestoppers and speak to them anonymously on 0800 555 111.