| State | Filing Deadline | Primary | Run-Off |
|---|---|---|---|
| Alabama | 04/04/08 | 06/03/08 | 07/15/08 |
| Alaska | 06/02/08 | 08/26/08 | |
| Arizona | 06/04/08 | 09/02/08 | |
| Arkansas | 03/10/08 | 05/20/08 | 06/10/08 |
| California | 03/07/08 | 06/03/08 | |
| Colorado | 05/29/08 | 08/12/08 | |
| Connecticut † | 05/24/08 | 08/12/08 | |
| Delaware | 07/25/08 | 09/09/08 | |
| Florida | 05/02/08 | 08/26/08 | |
| Georgia | 05/02/08 | 07/15/08 | 08/05/08 |
| Hawaii | 07/22/08 | 09/20/08 | |
| Idaho | 03/21/08 | 05/27/08 | |
| Illinois | 11/05/07 | 02/05/08 | |
| Indiana | 02/22/08 | 05/06/08 | |
| Iowa | 03/14/08 | 06/03/08 | |
| Kansas | 06/10/08 | 08/05/08 | |
| Kentucky | 01/29/08 | 05/20/08 | |
| Louisiana * | 07/11/08 | 10/04/08 | 11/04/08 |
| Maine | 03/15/08 | 06/10/08 | |
| Maryland | 12/03/07 | 02/12/08 | |
| Massachusetts | 06/03/08 | 09/16/08 | |
| Michigan | 05/13/08 | 08/05/08 | |
| Minnesota ‡ | 07/15/08 | 09/09/08 | |
| Mississippi | 01/11/08 | 03/11/08 | 04/01/08 |
| Missouri | 03/25/08 | 08/05/08 | |
| Montana | 03/20/08 | 06/03/08 | |
| Nebraska | 03/03/08 | 05/13/08 | |
| Nevada | 05/16/08 | 08/12/08 | |
| New Hampshire | 06/13/08 | 09/09/08 | |
| New Jersey | 04/07/08 | 06/03/08 | |
| New Mexico | 02/12/08 | 06/03/08 | |
| New York | 07/10/08 | 09/09/08 | |
| North Carolina | 02/29/08 | 05/06/08 | 06/24/08 |
| North Dakota | 04/11/08 | 06/10/08 | |
| Ohio | 01/04/08 | 03/04/08 | |
| Oklahoma | 06/04/08 | 07/29/08 | 08/26/08 |
| Oregon | 03/11/08 | 05/20/08 | |
| Pennsylvania | 02/12/08 | 04/22/08 | |
| Rhode Island | 06/25/08 | 09/09/08 | |
| South Carolina | 03/31/08 | 06/10/08 | 06/24/08 |
| South Dakota | 03/25/08 | 06/03/08 | 06/17/08 |
| Tennessee | 04/03/08 | 08/07/08 | |
| Texas | 01/02/08 | 03/04/08 | 04/08/08 |
| Utah | 03/17/08 | 06/24/08 | |
| Vermont | 07/21/08 | 09/09/08 | |
| Virginia § | 04/11/08 | 06/10/08 | |
| Washington | 06/06/08 | 08/19/08 | |
| West Virginia | 01/26/08 | 05/13/08 | |
| Wisconsin | 07/08/08 | 09/09/08 | |
| Wyoming | 05/30/08 | 08/19/08 |
† Connecticut’s filing deadline is fourteen days after state party conventions are held. The Democratic convention was held on May 10, 2008. The Connecticut Republican Party did not hold a statewide convention this year, but did hold individual congressional district conventions, also on May 10, 2008.
‡ Minnesota Democrats held individual congressional district conventions throughout April and May and held a state convention June 6-8, 2008. Traditionally, the party endorses candidates at these conventions. These endorsees become all-but-official nominees, usually rendering the primary a mere formality.
§ The Virginia Republican Party chose to nominate its Senate candidate via convention rather than via primary election.
* Due to Hurricane Gustav, Louisiana moved its primary from Sept. 6, 2008 to Oct. 4, 2008. Run-offs for LA-02 and LA-04 will be held on Nov. 4th and the general election for those races will be held on Dec. 6th. All other races will conduct normal general elections on Nov. 4th.
Note: Sorting by runoff date is not available.
Source: FEC.gov (PDF) (p. 3-4).