The incident happened around 5:30 p.m. in the area of Markham Road and Eastpark Boulevard and involved a motorcycle and another vehicle, according to police.
The motorcycle rider was taken to hospital in life-threatening condition. He later died from his injuries.
The circumstances that led to the collision are unknown.
Toronto Fire and Police are on scene and Markham Rd. is closed from Blakemanor Avenue to Greencrest Raceway.
