The serious road crash happened on Wednesday at 7.50am as a black Renault Clio was traveling north on Stuart Street, East Kilbride, near the Village Inn, when it struck a man crossing the road.
Emergency Services attended and the 80-year old pedestrian was taken to the Queen Elizabeth University Hospital with serious injuries.
The road was closed as crash scene investigators examined the site.
Sergeant Andrew Shearer said: “From our enquiries, we know there were several people in the area at the time of the incident and I would urge these people to contact us as their information could prove vital.
"I would also ask any motorists with dash cam devices to check their footage as they may have captured images which would assist us in establishing the full circumstances of what has happened.”
Anyone with information is asked to call Police Scotland on 101, quoting incident number 0428 of Wednesday, November 24.