He debuted in the Indy Racing League (IRL) in 2001, driving Penske's No. 68 Dallara IR-01-Oldsmobile car, at the season-opening Pennzoil Copper World Indy 200 at Phoenix to understand the series before the Indianapolis 500. Castroneves started 17th but retired with engine failure after race distance. He qualified 11th for his first Indianapolis 500 and led the final 52 laps to win the race at his first attempt.