Danny Richer, a spokesman for Montreal police, calls the deaths suspicious and says they are linked.
He says one of the bodies was found in an apartment in Montreal's Ville-Emard neighbourhood and the other was found nearby in a public place.
Investigators with Montreal's major crime unit are on the scene.
In a separate incident overnight, a 23-year-old man was shot and killed in Montreal's Mile End, marking the city's ninth homicide of the year.
A 21-year-old woman was also shot in the early morning incident, but her injuries weren't considered life threatening.