Vito Rizzuto was denied bail by the Quebec Court of Appeal after he was ordered deported to the United States to face charges linked to three mob murders.
He asked the high court to review that decision, but the justices refused to hear the case. The court, as is usual in leaves to appeal, gave no reasons for its decision.
Rizzuto's lawyers have a second appeal before the court over the way the case was handled by former justice minister Irwin Cotler.
The court has yet to rule on that matter.
U.S. authorities to try Rizzuto for conspiracy to murder three captains in the notorious Bonanno crime family in 1981.