Firefighters are trying to get control of a blaze just west of Toronto's downtown core.
The fire began just after 5am EST in a row of two-story buildings lining Queen Street West, a major east-west thoroughfare.
There are no reported injuries in the fire, which sent a smoky haze over much of the downtown area and has rush-hour pedestrians coughing as they head to work on Wednesday morning.
All residents living in second-floor apartments above ground-floor shops were able to get out in time and some nearby homes were evacuated.
The fire has gutted at least two buildings. (AP)