Democratic: 1 net loss Independent Democratic: 1 net loss Republican: 2 net gain Deaths: 2 Resignations: 1 Interim appointments: 3 Total seats with changes: 3 |- | Oregon(3) | nowrap | Wayne Morse (I) | style="front-size:80%" | Changed Political Parties April 30, 1955 | nowrap | Wayne Morse (D) | April 30, 1955 |- | West Virginia(1) | nowrap | Harley M. Kilgore (D) | style="font-size:80%" | Died February 28, 1956 | nowrap | William Laird III (D) | March 13, 1956 |- | South Carolina(2) | nowrap | Strom Thurmond (ID) | style="font-size:80%" | Resigned April 4, 1956, to trigger a contested primary as promised to voters | nowrap | Thomas A. Wofford (D) | April 5, 1956 |- | Kentucky(2) | nowrap | Alben W. Barkley (D) | style="font-size:80%" | Died April 30, 1956 | nowrap | Robert Humphreys (D) | June 21, 1956 |- | Kentucky(2) | nowrap | Robert Humphreys (D) | style="font-size:80%" | Successor elected November 6, 1956 | nowrap | John Sherman Cooper (R) | November 7, 1956 |- | South Carolina(2) | nowrap | Thomas A. Wofford (D) | style="font-size:80%" | Successor elected November 6, 1956 | nowrap | Strom Thurmond (D) | November 7, 1956 |- | West Virginia(1) | nowrap | William Laird III (D) | style="font-size:80%" | Successor elected November 6, 1956 | nowrap | Chapman Revercomb (R) | November 7, 1956 |} House of Representatives Replacements: 5 Democratic: no net change Republican: no net change Deaths: 9 Resignations: 3 Total seats with changes: 12 |- | | Vacant | Rep. Dwight L. Rogers died during the previous congress after having been re-elected.Successor elected January 11, 1955. | nowrap | Paul Rogers (D) | January 11, 1955 |- | | nowrap| John Dingell Sr. (D) | Died September 19, 1955.Successor elected December 13, 1955. | nowrap | John Dingell (D) | December 13, 1955 |- | | nowrap| Vera Buchanan (D) | Died November 26, 1955.Successor elected January 24, 1956. | nowrap | Elmer J. Holland (D) | January 24, 1956 |- | | nowrap| Sidney A. Fine (D) | Resigned January 2, 1956.Successor elected February 7, 1956. | nowrap | James C. Healey (D) | February 7, 1956 |- | | nowrap| Chauncey W. Reed (R) | Died February 9, 1956Seat remained unfilled until next term. | colspan=2 | Vacant |- | | nowrap| William T. Granahan (D) |