Police were called at around 10:15 p.m. after someone saw a man's body lying in the middle of the street near the corner of Saint-Michel Boulevard and Michel-Ange Street.
Officers and paramedics responded to the call, and the man was declared dead on site.
"Upon their arrival they found the body of a man in his 40s, with serious wounds to his upper-body. We're talking about gunshot wounds," said Const. Francois Collard with the Montreal Police.
Collard said police have not yet arrested any suspects, and the motive for the killing is unknown.
This is Montreal's 18th homicide of the year, compared to 17 at the same time last year.