South Yorkshire Police said the 25-year-old suffered a ‘life-changing arm injury' and had his car stolen after being attacked by a gang of men when he pulled over on East Bawtry Road, Whiston, at around 10.50pm on Sunday.
The driver, who was travelling alone, reportedly pulled over close to the junction with Lease Gate Road and was approached by a group of unknown men before being attacked.
During the violence his hand was severed.
The attackers, who got out of a dark blue coloured vehicle, drove off in the victim’s white Mercedes Benz C220.
The victim was taken to Rotherham Hospital where a surgeon re-attached his hand.
Anyone with information should call 101 and quote incident 985 of April 7 or Crimestoppers, anonymously, on 0800 555 111.