It started on the top floor of a three-storey building on Irvine Street at around 10 o'clock.
Fire platoon Capt. Steve Fraser says everyone was already out by the time they arrived.
"About 30 people had evacuated the building. We brought in — we call it a city transit bus to the scene to provide temporary shelter for the people that were outside, because it was minus 20, pretty cold last night," he says.
It took crews about 10 minutes to bring the fire under control.
Fraser says most people were able to return to their units on the first two floors.
The Canadian Red Cross is assisting those still out of their homes.
Fraser says the damage was mostly contained to one unit. It appears the fire started in a bedroom and was caused by careless smoking.