Twelve judges from Madrid's national court announced their decision to reject Mr Noye's appeal against extradition to Britain.
The extradition request, submitted last September by Kent police, was approved by the Spanish court last month.
Mr Noye had argued vehemently against being sent home at a hearing in the top-security Madrid courtroom in February, saying that he would not receive a fair trial. He argued that the press had effectively judged him already. The appeal, which Mr Noye did not attend, was heard last Thursday.
Mr Noye insists that he had nothing to do with the stabbing to death of Stephen Cameron on a motorway slip-road near Swanley, Kent, nearly three years ago. The judges' decision must be formally approved by the Spanish cabinet today and Mr Noye may be put on a flight to Britain within days.
Mr Noye left Britain shortly after Mr Cameron was killed, prompting an international police man-hunt that stretched from Tenerife to Cyprus. He was arrested last August in the Spanish resort town of Barbate, near Cadiz, after a police raid on a restaurant where he was dining.
Mr Noye's main defence was that the ad hoc procedure by which he was identified did not stand up in Spanish law. But the Spanish judges ruled that Britain's case against him was "absolutely convincing", and that the extradition request was "watertight".