The Illinois general election was held on November 2, 2004.

For the primary election, turnout was 28.97%, with 2,067,824 votes cast.

This was the fourth consecutive presidential election in which Illinois had voted for the Democratic ticket.

Incumbent first-term Republican Senator Peter Fitzgerald did not seek reelection.

All 19 of Illinois’ seats in the United States House of Representatives were up for election in 2004.