Missouri was admitted to the Union on August 10, 1821. Its current U.S. senators are Republicans Josh Hawley (class 1, serving since 2019) and Eric Schmitt (class 3, serving since 2023). Francis Cockrell was Missouri's longest-serving senator (1875–1905). Missouri is one of fifteen states alongside Arizona, Colorado, Florida, Georgia, Hawaii, Idaho, Indiana, Louisiana, Maine, Massachusetts, Minnesota, Nevada, South Dakota and Utah to have a younger senior senator and an older junior senator.

List of senators

! rowspan=19 | 1 ! rowspan=5 | 1 ! rowspan=2 | 2 ! rowspan=6 | 3 ! rowspan=6 | 4 ! rowspan=4 | 2 ! rowspan=3 | 5 ! rowspan=4 | 3 ! 6 ! rowspan=5 | 4 ! rowspan=2 | 7 ! rowspan=2 | 8 ! rowspan=2 | 9 ! rowspan=5 | 5 ! 10 ! rowspan=2 | 11 ! rowspan=3 | 12 ! rowspan=18 | 6 ! 13 ! 14 ! rowspan=12 | 15 ! rowspan=9 | 16 ! rowspan=3 | 7 ! rowspan=15 | 8 ! 17 ! rowspan=5 | 18 ! 19 ! rowspan=4 | 20 ! rowspan=4 | 9 ! rowspan=7 | 21 ! rowspan=6 | 10 ! rowspan=4 | 22 ! 11 ! rowspan=3 | 12 ! rowspan=5 | 23 ! rowspan=15 | 13 ! rowspan=5 | 24 ! rowspan=11 | 25 ! rowspan=10 | 14 ! rowspan=13 | 26 ! rowspan=3 | 15 ! 16 ! rowspan=3 | 17 ! rowspan=6 | 18 ! rowspan=6 | 27 ! rowspan=6 | 19 ! rowspan=3 | 28