Alcohol is believed to be a factor in a single vehicle rollover near the Pasqua First Nation on Saturday morning.
Police say the vehicle had veered off a grid road and rolled end over end.
One of the occupants was airlifted to a Regina hospital with life-threatening injuries, while another occupant was taken to a nearby hospital with non-life threatening injuries.
Three people fled the vehicle on foot, but were located a short time later.
Police continue to investigate the crash.