Heavily-armed police raced to the scene on Wolfedale Road, near Dundas Street West and Mavis Road, around midnight where they found the 21-year-old victim suffering from at least one gunshot wound near the rear of the building.
The man was taken to a nearby trauma centre with life-threatening injuries. Peel Regional Police say the man is now in stable condition, according to the latest report from the hospital.
No arrests have been made and police have yet to release any information about suspects.
Anyone with information about the shooting is asked to contact police.