The 2004 V8 Supercar Championship Series was an Australian racing series for V8 Supercars. It began on 21 March 2004 at the Adelaide Street Circuit and ended on 5 December at Eastern Creek Raceway after 13 rounds. It was the sixth running of the V8 Supercar Championship Series. The series winner was also awarded the 45th Australian Touring Car Championship title by the Confederation of Australian Motor Sport. The championship was won by Marcos Ambrose of the Stone Brothers Racing.