Police say they received multiple 911 calls shortly after closing time on Sunday morning, regarding an incident at a bar on Maple Avenue, north of Dunlop Street West, in Barrie.
When police arrived at the scene, they found two men who had been stabbed.
One of the injured men was taken to a Toronto hospital for surgery, though police say both suffered serious injuries.
Police say they later arrested two men from Barrie nearby.
Any witnesses or anyone with information is asked to contact Det. Const. Jason Storey at 705-725-7025, ext. 2128.