| Alabama | Jeff Sessions | Republican | Re-elected, 63.4% | Vivian Davis Figures (Democratic) 36.5% |
| Alaska | Ted Stevens | Republican | Defeated, 46.6% | Mark Begich (Democratic) 47.8% Bob Bird (Alaska Independence) 4.2% David Haase (Libertarian) 0.8% Ted Gianoutsos (Independent) 0.4% |
| Arkansas | Mark Pryor | Democratic | Re-elected, 79.5% | Rebekah Kennedy (Green) 20.5% |
| Colorado | Wayne Allard | Republican | Retired, Democratic victory | Mark Udall (Democratic) 52.8% Bob Schaffer (Republican) 42.5% Doug Campbell (Constitution) 2.6% Bob Kinsey (Green) 2.1% |
| Delaware | Joe Biden | Democratic | Re-elected, 64.7% | Christine O'Donnell (Republican) 35.3% |
| Georgia | Saxby Chambliss | Republican | General: Advanced to runoff, 49.8% Runoff: Re-elected, 57.4% | Jim Martin (Democratic) General: 46.8%; Runoff: 42.6% Allen Buckley (Libertarian) General: 3.4% (eliminated) |
| Idaho | Larry Craig | Republican | Retired, Republican victory | Jim Risch (Republican) 57.7% Larry LaRocco (Democratic) 34.1% Rex Rammell (Independent) 5.4% Kent Marmon (Libertarian) 1.5% "Pro-Life" (Independent) 1.3% |
| Illinois | Richard Durbin | Democratic | Re-elected, 67.8% | Steve Sauerberg (Republican) 28.5% Kathy Cummings (Green) 2.2% Larry Stafford (Libertarian) 0.9% Chad Koppie (Constitution) 0.5% |
| Iowa | Tom Harkin | Democratic | Re-elected, 62.7% | Christopher Reed 37.3% |
| Kansas | Pat Roberts | Republican | Re-elected, 60.0% | Jim Slattery (Democratic) 36.4% Randall Hodgkinson (Libertarian) 2.1% Joseph Martin (Reform) 1.3% |
| Kentucky | Mitch McConnell | Republican | Re-elected, 53.0% | Bruce Lunsford (Democratic) 47.0% |
| Louisiana | Mary Landrieu | Democratic | Re-elected, 52.1% | John Kennedy (Republican) 45.7% Richard Fontanesi (Libertarian) 1.0% Jay Patel (Independent) 0.7% Robert Stewart (Independent) 0.5% |
| Maine | Susan Collins | Republican | Re-elected, 61.3% | Tom Allen (Democratic) 38.6% |
| Massachusetts | John Kerry | Democratic | Re-elected, 65.8% | Jeff Beatty (Republican) 31.0% Robert Underwood (Libertarian) 3.2% |
| Michigan | Carl Levin | Democratic | Re-elected, 62.7% | Jack Hoogendyk (Republican) 33.8% Scott Boman (Libertarian) 1.6% Harley Mikkelson (Green) 0.9% Michael Nikitin (Constitution) 0.6% Doug Dern (Natural Law) 0.4% |
| Minnesota1 | Norm Coleman | Republican | Defeated, 41.98% | Al Franken (DFL) 41.99% Dean Barkley (MIP) 15.15% Charles Aldrich (Libertarian) 0.48% James Niemackl (Constitution) 0.31 Write-ins 0.08% |
| Mississippi | Thad Cochran | Republican | Re-elected, 61.4% | Erik Fleming (Democratic) 38.6% |
| Mississippi2 | Roger Wicker | Republican | Elected, 55.0% | Ronnie Musgrove (Democrat) 45.0% |
| Montana | Max Baucus | Democratic | Re-elected, 72.9% | Bob Kelleher (Republican) 27.1% |
| Nebraska | Chuck Hagel | Republican | Retired, Republican victory | Mike Johanns (Republican) 57.5% Scott Kleeb (Democratic) 40.1% Kelly Rosberg (Nebraska) 1.4% Steve Larrick (Green) 1.0% |
| New Hampshire | John E. Sununu | Republican | Defeated, 45.2% | Jeanne Shaheen (Democratic) 51.7% Ken Blevens (Libertarian) 3.1% |
| New Jersey | Frank Lautenberg | Democratic | Re-elected, 56.0% | Dick Zimmer (Republican) 42.0% Jason Scheurer (Libertarian) 0.5% J. M. Carter (Independent) 0.5% Daryl Mikell Brooks (Independent) 0.5% Jeffrey Boss (Independent) 0.3% Sara Lobman (Socialist Workers) 0.3% |
| New Mexico | Pete Domenici | Republican | Retired, Democratic victory | Tom Udall (Democratic) 61.3% Steve Pearce (Republican) 38.7% |
| North Carolina | Elizabeth Dole | Republican | Defeated, 44.2% | Kay Hagan (Democratic) 52.7% Chris Cole (Libertarian) 3.1% |
| Oklahoma | Jim Inhofe | Republican | Re-elected, 56.7% | Andrew Rice (Democratic) 39.2% Stephen Wallace (Independent) 4.1% |
| Oregon | Gordon Smith | Republican | Defeated, 45.6% | Jeff Merkley (Democratic) 48.9% Dave Brownlow (Constitution) 5.2% |
| Rhode Island | Jack Reed | Democratic | Re-elected, 73.4% | Robert Tingle (Republican) 26.6% |
| South Carolina | Lindsey Graham | Republican | Re-elected, 57.5% | Bob Conley (Democratic) 42.3% |
| South Dakota | Tim Johnson | Democratic | Re-elected, 62.5% | Joel Dykstra (Republican) 37.5% |
| Tennessee | Lamar Alexander | Republican | Re-elected, 65.1% | Bob Tuke (Democratic) 31.6% Edward Buck (Independent) 1.3% Christopher Fenner (Independent) 0.5% Daniel Lewis (Libertarian) 0.4% Chris Lugo (Green) 0.4% Ed Lawhorn (Independent) 0.4% David Gatchell 0.3%(Independent) |
| Texas | John Cornyn | Republican | Re-elected, 54.8% | Rick Noriega (Democratic) 42.8% Yvonne Adams Schick (Libertarian) 2.3% |
| Virginia | John Warner | Republican | Retired, Democratic victory | Mark Warner (Democratic) 65.0% Jim Gilmore (Republican) 33.7% Bill Redpath (Libertarian) 0.6% Gail Parker (Independent Green) 0.6% |
| West Virginia | Jay Rockefeller | Democratic | Re-elected, 63.7% | Jay Wolfe (Republican) 36.3% |
| Wyoming | Mike Enzi | Republican | Re-elected, 75.6% | Chris Rothfuss (Democratic) 24.3% |
| Wyoming3 | John Barrasso | Republican | Elected, 73.4% | Nick Carter (Democratic) 26.5% |