There was a crash in the Villeray district Friday afternoon involving a cylist and a truck.
It happened at the corner of de Castelneau and St Dominique.
According to police, witnesses say the cyclist ran a stop sign.
"The police arrived on scene, they located the cyclist, a young male, lying on the ground with serious injury to the head and leg, transferred to the hospital in critical condition", said police spokesman Benoit Boisselle.
The cyclist is 24-years old.
Investigators have been on the scene.