Firefighters found the body after quickly putting out a small fire in the house, at 3rd Street and 97th Avenue. Neighbours had seen smoke coming from the split-level home.
The body was in the stairwell from the basement to the ground floor.
The woman owned the home and was the only person inside when the fire department arrived.
Lieut. Ana Rodriguez of the Laval police said the fire crew called police because they smelled gasoline and found a red jerry can inside.
Police investigators are looking into whether it was an incident of arson and, if so, who set the fire.