The first crash occurred in Richmond Hill on Sunday morning, when a motorcycle collided with a taxi.
York Regional Police say the collision happened at Highway 7 and Leslie Street, at about 6:15 a.m. ET.
The driver of the motorcycle was taken to hospital, where he later died from his injuries.
The taxi driver suffered minor injuries in the crash.
Hours after the York Region crash, the Ontario Provincial Police responded to a serious collision at the intersection of Highway 10 and Old Baseline Road in Caledon, Ont.
Police believe a pickup truck that was travelling south on Highway 10 struck a motorcycle that was turning left onto Old Baseline Road.
The motorcyclist, a 49-year-old Mississauga man, was pronounced dead at the scene. His name has not been released.
The pickup truck driver and his passenger were not injured.
The crash remains under investigation.