| Alabama | Richard C. Shelby | Republican | Re-elected, 63.2% | Clayton Suddith (Democrat) 36.7% |
| Alaska | Frank Murkowski | Republican | Re-elected, 74.5% | Joe Sonneman (Democrat) 19.7% Jeffrey Gottlieb (Green) 3.2% Scott Kohlhaas (Libertarian) 2.3% |
| Arizona | John McCain | Republican | Re-elected, 68.7% | Ed Ranger (Democrat) 27.2% John C. Zajac (Libertarian) 2.3% Bob Park (Reform) 1.8% |
| Arkansas | Dale L. Bumpers | Democratic | Retired: Democratic victory | Blanche Lincoln (Democrat) 55.1% Fay Boozman (Republican) 42.2% Charley E. Heffley (Reform) 2.7% |
| California | Barbara Boxer | Democratic | Re-elected, 53% | Matt Fong (Republican) 43% Ted Brown (Libertarian) 1.1% Timothy R. Erich (Reform) 1% H. Joseph Perrin, Sr. (American Independent) 0.7% Ophie C. Beltran (Peace & Freedom) 0.6% Brian M. Rees (Natural Law) 0.6% |
| Colorado | Ben Nighthorse Campbell | Republican | Re-elected, 62.5% | Dottie Lamm (Democrat) 35% David S. Segal (Libertarian) 1% Kevin Swanson (American Constitution) 0.7% Jeffrey Peckman (Natural Law) 0.3% John Heckman (Concerns of People) 0.2% Gary Swing (Pacifist) 0.1% |
| Connecticut | Christopher Dodd | Democratic | Re-elected, 65.1% | Gary Franks (Republican) 32.4% William Kozak (Concerned Citizens) 1.3% Lois A. Grasso (Term Limits) 0.7% Wildey Moore (Libertarian) 0.5% |
| Florida | Bob Graham | Democratic | Re-elected, 62.5% | Charlie Crist (Republican) 37.5% |
| Georgia | Paul Coverdell | Republican | Re-elected, 52.3% | Michael Coles (Democrat) 45.3% Bertil Armin Loftman (Libertarian) 2.5% |
| Hawaii | Daniel Inouye | Democratic | Re-elected, 79.2% | Crystal Young (Republican) 17.8% Lloyd Mallan (Libertarian) 3% |
| Idaho | Dirk Kempthorne | Republican | Retired: Republican victory | Mike Crapo (Republican) 69.5% Bill Mauk (Democrat) 28.4% George J. Mansfeld (Natural Law) 2% |
| Illinois | Carol Moseley-Braun | Democratic | Defeated, 47.4% | Peter Fitzgerald (Republican) 50.3% Don A. Torgersen (Reform) 2.2% Raymond W. Stalker (U.S. Taxpayers) 0.01% |
| Indiana | Daniel R. Coats | Republican | Retired: Democratic victory | Evan Bayh (Democrat) 63.7% Paul Helmke (Republican) 34.8% Rebecca Sink-Burris (Libertarian) 1.5% |
| Iowa | Chuck Grassley | Republican | Re-elected, 68.4% | David Osterberg (Democrat) 30.5% Susan Marcus (Natural Law) 0.8% Margaret Trowe (Socialist Workers) 0.3% |
| Kansas | Sam Brownback | Republican | Re-elected, 65.3% | Paul Feleciano Jr. (Democrat) 31.6% Tom Oyler (Libertarian) 1.6% Alvin Bauman (Reform) 1.5% |
| Kentucky | Wendell Ford | Democratic | Retired: Republican victory | Jim Bunning (Republican) 49.7% Scotty Baesler (Democrat) 49.2% Charles R. Arbegust (Reform) 1.1% |
| Louisiana | John Breaux | Democratic | Re-elected, 64% | Jim Donelon (Republican) 32% |
| Maryland | Barbara Mikulski | Democratic | Re-elected, 70.5% | Ross Pierpont (Republican) 29.5% |
| Missouri | Kit Bond | Republican | Re-elected, 52.7% | Jay Nixon (Democrat) 43.8% Tamara Millay (Libertarian) 2.0% Curtis Frazier (U.S. Taxpayers) 1.0% James F. Newport (Reform) 0.5% |
| Nevada | Harry Reid | Democratic | Re-elected, 47.9% | John Ensign (Republican) 47.8% Michael Cloud (Libertarian) 1.9% None of These Candidates 1.8% Michael E. Williams (Natural Law) 0.6% |
| New Hampshire | Judd Gregg | Republican | Re-elected, 67.8% | George Condodemetraky (Democrat) 28.2% Brian Christeson (Libertarian) 2.4% Roy Kendel (Independent) 1.5% |
| New York | Al D'Amato | Republican | Defeated, 44.1% | Chuck Schumer (Democrat) 54.6% Corinne E. Kurtz (Marijuana Reform) 0.7% Joel Kovel (Green) 0.3% William P. Mc Millen (Libertarian) 0.2% Rose Ana Berbeo (Socialist Workers) 0.1% |
| North Carolina | Lauch Faircloth | Republican | Defeated, 47% | John Edwards (Democrat) 51.2% Barbara Howe (Libertarian) 1.8% |
| North Dakota | Byron Dorgan | Democratic | Re-elected, 63.1% | Donna Nalewaja (Republican) 35.2% Harley McLain (Libertarian) 1.7% |
| Ohio | John Glenn | Democratic | Retired: Republican victory | George Voinovich (Republican) 56.5% Mary Boyle (Democrat) 43.5% |
| Oklahoma | Don Nickles | Republican | Re-elected, 66.4% | Don Carroll (Democrat) 31.3% Mike Morris (Independent) 1.8% Argus W. Yandell, Jr. (Independent) 0.5% |
| Oregon | Ron Wyden | Democratic | Re-elected, 61% | John Lim (Republican) 33.8% Karen Moskowitz (Green) 2.0% Jim Brewster (Libertarian) 1.6% Michael A. Campbell (Natural Law) 0.8% Dean M. Braa (Socialist) 0.7% |
| Pennsylvania | Arlen Specter | Republican | Re-elected, 61.3% | Bill Lloyd (Democrat) 34.8% Dean Snyder (Constitution) 2.3% Jack Iannantuono (Libertarian) 1.6% |
| South Carolina | Fritz Hollings | Democratic | Re-elected, 52.7% | Bob Inglis (Republican) 45.7% Richard Quillian (Libertarian) 1.6% |
| South Dakota | Tom Daschle | Democratic | Re-elected, 62.1% | Ron Schmidt (Republican) 36.4% Byron Dale (Libertarian) 1.4% |
| Utah | Robert Foster Bennett | Republican | Re-elected, 64% | Scott Leckman (Democrat) 33% Gary R. Van Horn (Independent American) 3% |
| Vermont | Patrick Leahy | Democratic | Re-elected, 72.2% | Fred Tuttle (Republican) 22.5% Hugh Douglas (Libertarian) 2.0% Barry M. Nelson (Independent) 1.4% Bob Melamede (Vermont Grassroots) 1.2% Jerry Levy (Liberty Union) 0.6% |
| Washington | Patty Murray | Democratic | Re-elected, 58.4% | Linda Smith (Republican) 41.6% |
| Wisconsin | Russ Feingold | Democratic | Re-elected, 50.6% | Mark Neumann (Republican) 48.4% Robert R. Raymond (U.S. Taxpayers) 0.5% Tom Ender (Libertarian) 0.3% Eugene A. Hem (Independent) 0.2% |