Montreal police say it is the 28th homicide of the year on the Montreal territory.
Emergency crews were called to what appeared to be a collision between two cars near the corner of Cote Sainte-Catherine Road and Darlington Avenue, in the Côte-des-Neiges district.
But Const. Raphael Bergeron said the victim's injuries did not match the accident.
The 45-year-old taxi driver was rushed to hospital where he died.
Officers are on the scene where they are trying to determine what kind of weapon was used.