The Ontario Fire Marshal's office is on the scene of a house fire in the Dupont Street and Lansdowne Avenue area.
Crews arrived on the scene around 3:30 a.m. after a 9-1-1 call for a fire in the three-storey home on Sarnia Avenue.
Two people in the home were accounted for, but a third person, who was identified as a 62-year-old man was not.
The man was found by fire fighters on the second floor of the building and rushed to hospital with life-threatening injuries. He was pronounced dead a short time later.
Crews made quick work of the fire, it was knocked down at 3:48 a.m.
Deputy Chief Tony Bavota told CP24 there were working smoke alarms in the home.
No word on what started the fire, investigators are working with the Fire Marshal's office to determine the cause.
With files from CP24