The man, woman and two children are recovering from smoke inhalation, according to Urgences Santé.
“There was a lot of smoke and people had difficulty breathing,” said Marc-André Gagnon, the chief of operations.
Sixty firefighters responded to the call at about 2:30 a.m. in the Rosemont neighbourhood, near the corner of Bélanger Street and Fabre Street.
The fire started on the first floor and then spread to two other apartments.
A total of 10 residents were forced out of their homes and the fire caused an estimated $75,000 worth of damage.
Investigators are on the scene to determine the cause of the fire.