According to a statement, Melfort, Sask. RCMP officers were dispatched to the collision at about 12:30 a.m. Sunday.
The crash happened on Highway 6 approximately 10 kilometres north of Watson, Sask. Watson is about 158 kilometres east of Saskatoon.
RCMP learned from the investigation that a minivan had collided with a truck towing a boat on a trailer.
Police say a 43-year-old man from Spalding, Sask., was the driver and only person in the minivan when the collision happened.
A 42-year-old man from Melfort, who was the driver of the truck, and a 35-year-old man from Pickerel Lake, Sask., were in the truck.
RCMP declared all three individuals deceased at the scene. The families have been notified, police said.
Highway 6 was shut down for several hours during the initial portion of the investigation.
Melfort RCMP and a Saskatchewan RCMP traffic reconstructionist are continuing the investigation.