The 48-year-old was found lying in Drumbathie Road, Airdrie, North Lanarkshire, at around 12.25am today.
He was taken to Monklands Hospital in the town but died a short time later, police said.
Officers are investigating the death and believe he was hit by a car which did not stop. They are appealing for any witnesses and asked drivers who used the road between 11.50pm yesterday and 12.25am today to check their vehicles for damage.
Police said the driver of the car involved may not have been aware of any collision.
Sergeant David Stenhouse said: "Inquiries are continuing to establish the exact cause of his death, however at this time we believe that the victim may have been struck by a vehicle which didn't stop.
"Officers are carrying out inquiries in the local area and studying CCTV footage in an effort to gather more information.
"At this time, I would urge anyone who may have witnessed this incident take place, or who may have information that will assist this police investigation, to come forward.
"The driver of the vehicle concerned may be unaware that they had struck someone and I would urge anyone who thinks they may have been involved in an incident or were driving between 11.50pm on Sunday night and 12.25am on Monday morning in Drumbathie Road to contact police.
"The vehicle involved may have sustained damage, and I would ask anyone who has noticed such a vehicle to contact police. If someone has seen a car parked in an unusual place, or has any suspicions about a vehicle, then please come forward."
Anyone with information can contact police on the non-emergency 101 number, or anonymously via Crimestoppers on 0800 555 111.