The 2005 Menards Infiniti Pro Series was the fourth season of the series under the Indy Racing League ownership, and the 20th in Indy NXT combined history, as officially recognized by IndyCar. All teams used Dallara IL-02 chassis and Infiniti engines, a combination that was raced for the first time on road courses.[1]
In a consistent, and almost winless, rookie year, Wade Cunningham became the champion by scoring his only win of the year in the final round at California Speedway. Driving for the storied Brian Stewart Racing, Cunningham led the championship from the sixth round, despite not scoring a win or a pole position in the first 12 races. At the end of the year, he had a total of 10 podium finishes, seven of those in second place.
Jeff Simmons returned to the series full-time, and recovered from a bad first half of the season to score four wins. He repeated his second place finish in the standings from 2003 by beating Travis Gregg, who scored a field-record six pole positions and won three races with defending champions Sam Schmidt Motorsports. Jaime Camara, also driving for Schmidt, won the Freedom 100 from pole position ahead of Cunningham, adding another win at Nashville to finish fifth behind fellow rookie Nick Bussell.
With the introduction of road course racing in the IRL IndyCar Series, the Infiniti Pro Series followed suit with four road course races, including his first race outside of the IndyCar bill, the Liberty Challenge held at the Indianapolis road course during the controversial U. S. Grand Prix weekend. Driving a partial schedule, 18-year old Marco Andretti set the standard at the road course races with three wins, being only beaten by Simmons at Watkins Glen. These results, along with a podium finish at Kentucky, were enough to finish 10th in the standings before his IndyCar promotion.
Five years after Team Green left Indy Lights, Andretti Green Racing entered the Infiniti Pro Series for the first time at selected rounds. Newly formed IndyCar team Vision Racing also entered the series, while Roth Racing and Racing Professionals went on to contest the full season. Genoa Racing returned and J. L. West Motorsports also entered from the beginning with both teams downsizing halfway through the year, while Michael Crawford Motorsports also debuted with a partial schedule. On the other hand, Mo Nunn Racing's Pro Series operation was disbanded along with the main team, and both Keith Duesenberg Racing and Roquin Motorsports left the series.
The series had at least 11 drivers at each round, with 15 competitors at Phoenix and 18 drivers in the Freedom 100. Eight drivers competed in every race, plus Jay Drake at all but one race. At Chicagoland, Sarah McCune became the first woman in series history to score a pole, this being the only start of her career. Marty Roth competed again in both the Indianapolis 500 and the Freedom 100, where he was one of three starters with previous IndyCar experience along with Simmons and Jon Herb, the winner at Phoenix earlier in the year.
The Infiniti Pro Series accompanied the new IndyCar road course events at St. Petersburg, Sonoma and Watkins Glen, while also adding a fourth road course event in Indianapolis as part of the Formula 1United States Grand Prix bill. The oval races at Kansas and Michigan were removed from the schedule, which grew from 12 events to 14. The Texas date was moved to June after the fall event was discontinued by IndyCar, with California Speedway serving as the venue for the season finale.