State> | gcolor="#cccccc"|Incumbent | bgcolor="#cccccc"|Party | bgcolor="#cccccc"|Status | bgcolor="#cccccc"|Opposing Candidates |
| a href="/encyclopedia/Alabama" title="Alabama">Alabama1 | George R. Swift | Democrat | Retired: Democrat victory, unopposed | John Sparkman (Democrat) |
| a href="/encyclopedia/Arizona" title="Arizona">Arizona | Ernest W. McFarland | Democrat | Re-elected, 69.2 - 30.1 | Ward S. Powers (Republican) |
| a href="/encyclopedia/California" title="California">California | William F. Knowland | Republican | Re-elected, 54.1 - 44.2 | Will Rogers, Jr. (Democrat) |
| a href="/encyclopedia/Connecticut" title="Connecticut">Connecticut | Thomas C. Hart | Republican | Retired: Republican victory, 56.1 - 40.7 | Raymond E. Baldwin (Republican) Joseph M. Tone (Democrat) |
| a href="/encyclopedia/Delaware" title="Delaware">Delaware | James M. Tunnell | Democrat | Defeated, 55.2 - 44.9 | John J. Williams (Republican) |
| a href="/encyclopedia/Florida" title="Florida">Florida | Charles O. Andrews | Democrat | Retired: Democrat victory, 78.7 - 21.4 | Spessard L. Holland (Democrat) J. Harry Schad (Republican) |
| a href="/encyclopedia/Idaho" title="Idaho">Idaho2 | Charles C. Gossett | Democrat | Defeated in primary: Republican victory, 58.6 - 41.4 | Henry C. Dworshak (Republican) George E. Donart (Democrat) |
| a href="/encyclopedia/Indiana" title="Indiana">Indiana | Raymond E. Willis | Republican | Retired: Republican victory, 52.4 - 46.8 | William E. Jenner (Republican) Henry F. Schricker (Democrat) |
| a href="/encyclopedia/Kentucky" title="Kentucky">Kentucky3 | William A. Stanfill | Republican | Retired: Republican victory, 53.3 - 46.5 | John S. Cooper (Republican) John Y. Brown (Democrat) |
| a href="/encyclopedia/Maine" title="Maine">Maine | Ralph O. Brewster | Republican | Re-elected, 63.6 - 36.5 | Peter M. MacDonald (Democrat) |
| a href="/encyclopedia/Maryland" title="Maryland">Maryland | George L. P. Radcliffe | Democrat | Retired: Democrat victory, 50.2 - 49.8 | Herbert R. O'Conor (Democrat) David J. Markey (Republican) |
| a href="/encyclopedia/Massachusetts" title="Massachusetts">Massachusetts | David I. Walsh | Democrat | Defeated, 59.6 - 39.7 | Henry Cabot Lodge, Jr. (Republican) |
| a href="/encyclopedia/Michigan" title="Michigan">Michigan | Arthur H. Vandenberg | Republican | Re-elected, 67.1 - 32.0 | James H. Lee (Democrat) |
| a href="/encyclopedia/Minnesota" title="Minnesota">Minnesota | Henrik Shipstead | Republican | Retired: Republican victory, 58.9 - 39.8 | Edward J. Thye (Republican) Theodore Jorgenson (Democrat) |
| a href="/encyclopedia/Mississippi" title="Mississippi">Mississippi | Theodore G. Bilbo | Democrat | Re-elected, unopposed | |
| a href="/encyclopedia/Missouri" title="Missouri">Missouri | Frank P. Briggs | Democrat | Defeated, 52.7 - 47.1 | James P. Kem (Republican) |
| a href="/encyclopedia/Montana" title="Montana">Montana | Burton K. Wheeler | Democrat | Defeated in Primary: Republican victory, 53.5 - 45.4 | Zales N. Ecton (Republican) Leif Erickson (Democrat) |
| a href="/encyclopedia/Nebraska" title="Nebraska">Nebraska | Hugh Butler | Republican | Re-elected, 70.8 - 29.2 | John E. Mekota (Democrat) |
| a href="/encyclopedia/Nevada" title="Nevada">Nevada | Edward P. Carville | Democrat | Defeated in primary: Republican victory, 55.2 - 44.8 | George W. Malone (Republican) Berkeley L. Bunker (Democrat) |
| a href="/encyclopedia/New-Jersey" title="New Jersey">New Jersey | H. Alexander Smith | Republican | Re-elected, 58.5 - 40.1 | George E. Brunner (Democrat) |
| a href="/encyclopedia/New-Mexico" title="New Mexico">New Mexico | Dennis Chavez | Democrat | Re-elected, 51.5 - 48.5 | Patrick J. Hurley (Republican) |
| a href="/encyclopedia/New-York" title="New York">New York | James M. Mead | Democrat | Retired: Republican victory, 52.6 - 47.6 | Irving M. Ives (Republican) Herbert M. Lehman (Democrat) |
| a href="/encyclopedia/North-Dakota" title="North Dakota">North Dakota | William Langer | Republican | Re-elected, 53.3 - 23.5 - 23.2 | Arthur E. Thompson (Independent) Abner B. Larson (Democrat) |
| a href="/encyclopedia/North-Dakota" title="North Dakota">North Dakota4 | Milton R. Young | Republican | Re-elected, 55.5 - 27.4 - 15.2 | William Lanier (Democrat) Gerald P. Nye (Independent) |
| a href="/encyclopedia/Ohio" title="Ohio">Ohio | James W. Huffman | Democrat | Defeated, 57.0 - 42.4 | John W. Bricker (Republican) |
| a href="/encyclopedia/Pennsylvania" title="Pennsylvania">Pennsylvania | Joseph F. Guffey | Democrat | Defeated, 59.3 - 39.8 | Edward Martin (Republican) |
| a href="/encyclopedia/Rhode-Island" title="Rhode Island">Rhode Island | Peter G. Gerry | Democrat | Retired: Democrat victory, 55.1 - 44.9 | J. Howard McGrath (Democrat) W. Gurnee Dwyer (Republican) |
| a href="/encyclopedia/South-Dakota" title="South Dakota">South Dakota | Harlan J. Bushfield | Republican | Retired: Republican victory, 59.3 - 40.7 | Karl E. Mundt (Republican) John A. Engel (Democrat) |
| a href="/encyclopedia/Tennessee" title="Tennessee">Tennessee | Kenneth D. McKellar | Democrat | Re-elected, 66.6 - 26.2 | W. B. Ladd (Republican) |
| a href="/encyclopedia/Texas" title="Texas">Texas | Tom Connally | Democrat | Re-elected, 88.5 - 11.5 | Murray C. Sells (Republican) |
| a href="/encyclopedia/Utah" title="Utah">Utah | Abe Murdock | Democrat | Defeated, 51.2 - 48.8 | Arthur V. Watkins (Republican) |
| a href="/encyclopedia/Vermont" title="Vermont">Vermont | Warren R. Austin | Republican | Retired: Republican victory, 74.6 - 25.4 | Ralph E. Flanders (Republican) Charles P. McDevitt (Democrat) |
| a href="/encyclopedia/Virginia" title="Virginia">Virginia | Harry F. Byrd | Democrat | Re-elected, 64.9 - 30.5 | Lester S. Parsons (Republican) |
| a href="/encyclopedia/Virginia" title="Virginia">Virginia5 | Thomas G. Burch | Democrat | Retired: Democrat victory, 68.2 - 29.0 | A. Willis Robertson (Democrat) Robert H. Woods (Republican) |
| a href="/encyclopedia/Washington" title="Washington">Washington | Mon C. Wallgren | Democrat | Retired: Republican victory, 54.3 - 45.2 | Harry P. Cain (Republican) Hugh B. Mitchell (Democrat) |
| a href="/encyclopedia/West-Virginia" title="West Virginia">West Virginia | Harley M. Kilgore | Democrat | Re-elected, 50.3 - 49.7 | Thomas Sweeney (Republican) |
| a href="/encyclopedia/Wisconsin" title="Wisconsin">Wisconsin | Robert M. La Follette, Jr. | Progressive | Defeated in Republican primary: Republican victory, 61.3 - 37.4 | Joseph R. McCarthy (Republican) Howard J. McMurray (Democrat) |
| a href="/encyclopedia/Wyoming" title="Wyoming">Wyoming | Joseph C. O'Mahoney | Democrat | Re-elected, 56.2 - 43.8 | Harry B. Henderson (Republican)
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