Vitantonio Liuzzi
With support from Red Bull, Doornbos joined reigning International Formula 3000 champions Arden International for the 2004 FIA International Formula 3000 Championship. Partnered with Vitantonio Liuzzi, Doornbos claimed Rookie of the Year after finishing third in the championship. During the year, he took a fastest lap and four podium finishes, including a race win at Spa-Francorchamps.