Several former CART teams brought their full operations to the IRL, most notably major squads Chip Ganassi Racing and Andretti Green Racing, as well as former CART engine manufacturers Toyota and Honda, replacing Infiniti who shifted its efforts to the new feeder series Infiniti Pro Series.

Many of the IRL's old guard including Robbie Buhl, Greg Ray, and Buddy Lazier had difficulty competing in this new manufacturer-driven landscape.

The league also added its first international race this year, taking over the CART date at Twin Ring Motegi.

New Zealander Scott Dixon won the opening race of the season at Homestead and ran very consistently all year long to win his first title at the age of 23.

Gil de Ferran won Penske's third consecutive Indianapolis 500 in May and finished second to Dixon in the title race.

The finale however was marred by a severe incident that nearly killed former series' champion and Indy 500 winner Kenny Bräck.

Bräck would eventually recover; however, Tony Renna, a Ganassi development driver, lost his life in a test crash at Indianapolis after the season had officially ended.

Top ten results This race was held June 15 at Pikes Peak International Raceway.

Top ten results Note: 1 Tora Takagi had 23 points deducted at Texas Motor Speedway due to unacceptable driving.