Just before 4 p.m. Friday, there was a serious collision involving two vehicles at Airport Road near County Road 7 and 5 Sideroad in Mono.
As a result of the collision, a 20-year-old man from Scarborough was pronounced deceased at the scene.
A 21-year-old male was taken to a Toronto-area trauma center.
Two other males and one female were taken to hospital with minor injuries.
Airport Road was closed for several hours for an investigation.