A 30-year-old man was taken to hospital by STARS Air Ambulance on Wednesday night after a two-vehicle crash southwest of Turner Valley.
In a release, RCMP said a Honda SUV and a Dodge Caravan travelling in opposite directions collided on 466 Avenue around 9:05 p.m.
Police believe the 30-year-old man was the driver and only person in the SUV. He suffered serious injuries.
Three people in the minivan were taken to a Calgary hospital by ground ambulance with non-life threatening injuries.
The cause of the crash is still under investigation.
Turner Valley is approximately 45 kilometres south of Calgary.