The Mounties said the man was arrested without incident Thursday at about 7:40 a.m. in Montague.
Sgt. Leanne Butler said two people were found dead around 9:15 p.m. Wednesday inside a residence on St. Mary's Road south of Montague in Kings County.
Officers responded to the scene after a member of the public called 911.
Butler declined to disclose details about the victims or how they died, saying police would need permission from the coroner's office before doing so.
She would also not confirm reports that a shooting had taken place.
Roadblocks that were put in place on St. Mary's Road as police investigated were later removed.