Three men car-jacked a 20-year-old man at knifepoint in Portslade.
They attacked him so viciously as they took his purple Ford Fiesta that he needed hospital treatment.
Sussex Police said that they had arrested two 19-year-old men and a 22-year-old man, all local, on suspicion of robbery.
The suspects have been bailed until Tuesday 3 May while officers carry out further inquiries.
The victim was taken to the Royal Sussex County Hospital in Brighton for treatment to facial injuries after being punched repeatedly during the incident.
His car was taken just after midnight on Sunday (20 March).
An 18-year-old woman passenger was unhurt.
The car was taken in Sidehill Drive, Portslade, and found in the town a few hours later.
It is now being forensically examined.
Police urged witnesses to call on 0845 6070999 or to contact the independent charity Crimestoppers anonymously on 0800 555111.