Democrats participating in 01-SR121 | ||
| Daniel Akaka | s1o | HI Democrat Jr Senator |
| Joe Biden | s1o | DE Democrat Jr Senator |
| Barbara Boxer | s1o | CA Democratic incumbent |
| Jean Carnahan | s1o | MO Democrat Senator (Former) |
| Mark Dayton | s1o | MN Democrat Jr Senator |
| Russell Feingold | s1o | POTUS Democrat |
| Fritz Hollings | s1o | SC Former Democratic Sr Senator; retired 2004 |
| Ted Kennedy | s1o | MA Democrat Sr Senator |
| John Kerry | s1i | MA Democrat Jr Senator |
| Patrick Leahy | s1o | VT Democratic incumbent |
| Joseph Lieberman | s1o | CT Democratic Jr Senator; Gore's VP nominee; ran for Pres. 2004 |
| Jack Reed | s1o | RI Democrat Sr Senator |
| Paul Sarbanes | s1o | MD Democrat Sr Senator |
| Ron Wyden | s1o | OR Democratic incumbent |
Republicans participating in 01-SR121 | ||
| Susan Collins | s1o | ME Republican Jr Senator |
| Richard Lugar | s1o | IN Republican Sr Senator |
| John McCain | s1o | AZ Republican incumbent |
| Bob Smith | s1o | FL Republican challenger; former NH Senator; Constitution Party |
| Olympia Snowe | s1o | ME Republican Sr Senator |
| John Warner | s1o | VA Republican Sr Senator |
Independents participating in 01-SR121 |
| Democrats:
14
Republicans: 6 Independents: 0 |