Rizzuto, 67, was admitted to Sacre-Coeur Hospital on Sunday for pulmonary problems, the Canadian Broadcasting Corp. reported.
Known as Montreal's Teflon Don later in life, Rizzuto moved to Canada with his family from Sicily when he was 8 years old.
In 2007, Rizzuto was sentenced to 10 years in prison for a 2003 indictment for his role in the murders of three alleged gang leaders in 1981.
Susan Sarandon 'very excited' about daughter's pregnancy
Interpol investigating stolen passports on missing flight