The cars collided at full speed on Highway 158 in St-Canut.
Firefighters had to use the jaws of life to extract the victims.
A 50-year-old man was declared dead at the scene and two women in their 20s were taken to hospital with non-life-threatening injuries.
Investigators began reconstructing the scene Wednesday morning to try and piece together what happened.
They said it's not clear why the vehicles collided at full speed.