| Senator | State | Party | First elected | Reason for retirement |
| Lamar Alexander | Tennessee | Republican | 2002 | His brand of trying to compromise and pass laws is out of fashion |
| Pat Roberts | Kansas | Republican | 1996 | He would be 90 at the end of another term |
| Johnny Isakson | Georgia | Republican | 2004 | Poor health |
| Tom Udall | New Mexico | Democratic | 2008 | Not clear. He could have won easily. Maybe his is just tired of gridlock |
Senate Retirements 2020