The man was walking across Kilbowie Road in Clydebank, near Glasgow, near to its junction with Drumry Road at about 7.45pm on Saturday when he was struck by Renault Clio.
He was taken to the Western Infirmary in Glasgow, where he is being treated for head injuries. Hospital staff describe his condition as serious.
The female Renault driver, 62, is not thought to have been injured.
Constable Allan Moffat from the Road Policing Unit at Dumbarton Police Office said: "Inquiries are ongoing to establish the circumstances surrounding the crash and I would urge any witnesses, or anyone with information to contact Police Scotland on 101."
It came less than a week after a man died and another left in a critical condition in hospital after their car hit a tree on the A82 Great Western Road in Drumchapel, Glasgow.