The special primary election was held on April 11, 2006. A candidate who received a majority of the vote would have served out the rest of Cunningham's term. As no candidate won a simple majority, the top vote-getters in each party, Democrat Francine Busby and Republican Brian Bilbray, competed in a runoff special general election held on June 6, 2006, the same day that primaries were held for the November 2006 general election.
