Police were called shortly after 8:30 p.m. to a hospital on Hurontario Street and in Queensway West.
Police said the man entered the hospital with obvious signs of injury and was later pronounced dead.
The homicide office has been informed.
Police initially said the man sustained gunshot wounds, but later said the exact nature of his injuries was unclear.
They also stated that the circumstances surrounding the incident are unknown at this time.
No suspicious information has been provided.