G. Hatfield(D) | Lost nomination to the next term.Resigned early December 12, 1978.Successor appointed, having already been elected to the next term. | nowrap | Max Baucus(D) | December 15, 1978 |- | nowrap | Kansas(2) | nowrap | James B. Pearson(R) | Resigned December 23, 1978.Successor appointed, having already been elected to the next term. | nowrap | Nancy Kassebaum(R) | December 23, 1978 |- | nowrap | Mississippi(2) | nowrap | James Eastland(D) | Resigned December 27, 1978.Successor appointed, having already been elected to the next term. | nowrap | Thad Cochran(R) | December 27, 1978 |- | nowrap | Minnesota(2) | nowrap | Wendell R. Anderson(DFL) | Resigned December 29, 1978.Successor appointed, having already been elected to the next term. | nowrap | Rudy Boschwitz(R) | December 30, 1978 |- | nowrap | Wyoming(2) | nowrap | Clifford Hansen(R) | Resigned December 31, 1978.Successor appointed, having already been elected to the next term. | nowrap | Alan Simpson(R) | January 1, 1979 |- | nowrap | Virginia(2) | nowrap | William L. Scott(R) | Resigned January 1, 1979.Successor appointed, having already been elected to the next term. | nowrap | John Warner(R) | January 2, 1979 |} House of Representatives Replacements: 6 Democratic: 4 seat net loss Republican: 4 seat net gain Deaths: 6 Resignations: 21 Contested election: 0 Total seats with changes: 25 |- | | nowrap | Robert Bergland (DFL) | style="font-size:80%" | Resigned January 22, 1977, after being appointed United States Secretary of Agriculture | nowrap | Arlan Stangeland (R) | February 22, 1977 |- | | nowrap | Brock Adams (D) | style="font-size:80%" | Resigned January 22, 1977, after being appointed United States Secretary of Transportation | nowrap | John E. Cunningham (R) | May 17, 1977 |- | | nowrap | Andrew Young (D) | style="font-size:80%" | Resigned January 29, 1977, after being appointed United States Ambassador to the United Nations | nowrap | Wyche Fowler (D) | April 6, 1977 |- | | nowrap | Richard Alvin Tonry (D) | style="font-size:80%" | Forced to resign May 4, 1977 | nowrap | Bob Livingston (R) | August 27, 1977 |- | | nowrap | Ed Koch (D) | style="font-size:80%" | Resigned December 31, 1977, after being elected Mayor of New York City | nowrap | Bill Green (R) | February 14, 1978 |- | | nowrap | Herman Badillo (D) | style="font-size:80%"