Three people were taken to hospital after a head-on collision on Highway 28 just north of Peterborough on Sunday afternoon.
The crash around 2 p.m. near Mount Julian-Viamede Road in North Kawartha Township near the community of Woodview.
Police say a southbound vehicle crossed the centre line and struck a northbound vehicle.
A passenger in the northbound vehicle was extricated and suffered life-threatening injuries. The woman was airlifted to a Toronto hospital by Ornge air ambulance.
Both drivers were taken to hospital in Peterborough with non-life threatening injuries, OPP said.
OPP are investigating whether slick roads played a role in the crash. The highway was closed for several hours as OPP investigated.
The cause of the collision remains under investigation.