It happened yesterday at about 1.30pm on Creighton Avenue, Carlisle.
The man was struck by a Silver Vauxhall Corsa which failed to stop.
A spokesman for the police said: "We are appealing for witnesses following a fail to stop collision involving a car and a pedestrian yesterday (Jan 28) at around 1:30pm on Creighton Avenue, Carlisle.
"Officers were called by NWAS to the report.
"The pedestrian a 29-year-old man suffered significant injuries.
"The vehicle involved was a Silver Vauxhall Corsa.
Anyone with any information or who witnessed or has footage the collision is asked to contact police on 101 or Crime Stoppers anonymously on 0800 555 111.