The incumbent, Republican Jon Kyl, was elected to the Senate in 1994 and was re-elected to a second term in 2000; having previously spent eight years in the U.S. House of Representatives. Kyl's Democratic opponent for the general election was wealthy real-estate developer Jim Pederson, who served as the Arizona Democratic Party Chairman from 2001 to 2005. During his tenure, Pederson spent millions of dollars of his own money to help Democrats modernize and to elect Janet Napolitano as Governor of Arizona. The deadline for signing petition signatures to appear on the September 12, 2006 primary ballot was June 14, 2006.