The incident occurred on 29/10 at 2.12am on the A4 Bath Road, Kintbury crossroads in Hungerford.
The victim, a 48-year-old man, was walking along the road with another man when a vehicle collided with him.
The vehicle, which may have been a dark coloured hatchback, did not stop at the scene.
The victim sustained serious head, shoulder and back injuries and was taken to hospital for treatment where he remains.
Investigating officer Sergeant Andrew Fordyce of the Joint Operations Unit for Roads Policing, based at Three Mile Cross, said: “I would like to speak to anyone who may have seen two pedestrians walking along this road at about 2.10am.
“The vehicle involved in this collision is likely to have sustained damage as a result of this incident, and I would like to speak to anyone who saw any dark coloured medium sized hatchback vehicles on the road around the time this incident occurred.
“Anyone with any details which could help our investigation is asked to call the Thames Valley Police non-emergency number on 101.”
If you have any information relating to this case, please call 101 quoting reference ‘260 (29/10)’, or contact Crimestoppers anonymously.