She first drove in the IndyCar Series with Rahal Letterman Racing in 2005 and took three pole positions, equaling Tomas Scheckter's record of poles in a rookie season. She was named the Rookie of the Year for both the 2005 Indianapolis 500 and the 2005 IndyCar Series. She improved over the next two years with Rahal Letterman Racing in 2006 and later Andretti Green Racing in 2007. In 2008, Patrick followed up her Japan victory to place sixth overall in the drivers' standings. She improved on this to secure fifth the following season, which saw her finish a career-high third at the Indianapolis 500, the best performance by any woman at the race. Patrick's overall form declined during 2010, but she still managed two-second-places at oval tracks before leaving IndyCar after the 2011 season to focus on stock car racing full-time.