| Tuesday 17 February 2004 | Kentucky - Special Election House CD 6 |
| Tuesday 2 March 2004 | California - Primary
Maryland - Primary
Ohio - Primary |
| Tuesday 9 March 2004 | Texas - Primary
Mississippi - First Party Primary |
| Tuesday 16 March 2004 | Illinois - Primary |
| Tuesday 30 March 2004 | Mississippi - Second Party Primary (Runoff, if necessary) (cancelled) |
| Tuesday 13 April 2004 | Texas - Runoff (GOP: CDs 1, 10, 15, 17, 28; Railroad) |
| Tuesday 27 April 2004 | Pennsylvania - Primary |
| Tuesday 4 May 2004 | Indiana - Primary |
| Tuesday 11 May 2004 | West Virginia - Primary
Nebraska - Primary |
| Tuesday 18 May 2004 | Arkansas - Primary
Kentucky - Primary
Oregon - Primary |
| Tuesday 25 May 2004 | Idaho - Primary |
| Tuesday 1 June 2004 | Alabama - Primary
New Mexico - Primary
South Dakota - Primary, Special Election US House |
| Tuesday 8 June 2004 | Montana - Primary
New Jersey - Primary
Iowa - Primary
Maine - Primary
South Carolina - Primary
Virginia - Primary
North Dakota - Primary |
| Tuesday 22 June 2004 | Utah - Primary
South Carolina - Runoff (Senate Republican) |
| Tuesday 29 June 2004 | Alabama - Runoff (CD 5 Republican) |
| Tuesday 20 July 2004 | North Carolina - Primary & CD1 Special Election
Georgia - Primary |
| Tuesday 27 July 2004 | Oklahoma - Primary |
| Tuesday 3 August 2004 | Michigan - Primary
Missouri - Primary
Kansas - Primary |
| Thursday 5 August 2004 | Tennessee - Primary |
| Tuesday 10 August 2004 | Georgia - Primary Runoff (Senate-Dem, CD 6-Rep, CD 8-Rep)
Connecticut - Primary
Colorado - Primary |
| Tuesday 17 August 2004 | Wyoming - Primary
North Carolina - Second Primary (CD 5-Rep, CD 10-Rep, Public Instruction-Dem) |
| Tuesday 24 August 2004 | Alaska - Primary
Oklahoma - Runoff (no runoffs for statewide or federal offices) |
| Tuesday 31 August 2004 | Florida - Primary |
| Saturday 4 September 2004 | Guam - Primary Election |
| Tuesday 7 September 2004 | Nevada - Primary
Arizona - Primary |
| Saturday 11 September 2004 | Delaware - Primary
Virgin Islands - Primary Election |
| Tuesday 14 September 2004 | District of Columbia - Primary
Massachusetts - Primary
Minnesota - Primary
New Hampshire - Primary
Rhode Island - Primary
Vermont - Primary
Wisconsin - Primary
Washington - Primary
New York - Primary |
| Saturday 18 September 2004 | Hawaii - Primary |
| Tuesday 16 November 2004 | Mississippi - General Election Run-off (no statewide offices are subject to runoff) (cancelled)
American Samoa - Runoff (Territorial Governor) |
| Tuesday 23 November 2004 | Georgia - General Election Runoff (no runoffs for statewide offices) (cancelled) |
| Saturday 4 December 2004 | Louisiana - General Election Runoff (House CDs 3 and 7) |
| (no activity) | Northern Marianas
Puerto Rico |
