Police and emergency services were called to Brooklyn this evening following reports of a collision between a car and a pedestrian.
It is believed the pedestrian was struck by a Kia wagon on Geelong Road about 10.35pm.
The pedestrian, who is an unidentified man aged in his mid-20s, was taken to hospital where he remains with life-threatening injuries.
The driver of the Kia, a 39-year-old Kalkallo woman, was uninjured stopped to assist at the scene.
Westgate Highway Patrol are investigating the cause of the collision and are appealing for anyone with information to come forward.
Anyone who witnessed the crash, or who may have information regarding the identity of the pedestrian is urged to contact Crime Stoppers on 1800 333 000