Witnesses told police the 77-year-old man who was driving at a normal speed over the Concorde Bridge when he suddenly accelerated.
Police said the man lost control of the wheel while exiting the bridge heading towards towards the casino shortly before 8 p.m.
Images from the scene showed the vehicle standing almost upright on the casino's welcoming sign.
Montreal police Const. Anie Lemieux said the driver and his 76-year-old female passenger were declared dead on the scene.
Police officers redirected traffic around the crash site Tuesday night.
The casino is still accessible to the public.