Columns: District | Vacator | Reason for change | Successor | Date successor seated
Colorado At-large | James B. Belford (R) | Lost contested election December 13, 1877 | Thomas M. Patterson (D) | December 13, 1877 | California 4th | Romualdo Pacheco (R) | Lost contested election February 7, 1878 | Peter D. Wigginton (D) | February 7, 1878 | Louisiana 3rd | Chester B. Darrall (R) | Lost contested election February 20, 1878 | Joseph H. Acklen (D) | February 20, 1878 | Louisiana 5th | John E. Leonard (R) | Died March 15, 1878 | J. Smith Young (D) | November 5, 1878 | Massachusetts 3rd | Walbridge A. Field (R) | Lost contested election March 28, 1878 | Benjamin Dean (D) | March 28, 1878 | New York 16th | Terence J. Quinn (D) | Died June 18, 1878 | John M. Bailey (R) | November 5, 1878 | Nebraska At-large | Frank Welch (R) | Died September 4, 1878 | Thomas J. Majors (R) | November 5, 1878 | Michigan 1st | Alpheus S. Williams (D) | Died December 21, 1878 | Vacant | Not filled this term | Virginia 1st | Beverly B. Douglas (D) | Died December 22, 1878 | Richard L. T. Beale (D) | January 23, 1879 | Georgia 1st | Julian Hartridge (D) | Died January 8, 1879 | William B. Fleming (D) | February 10, 1879 | Texas 6th | Gustav Schleicher (D) | Died January 10, 1879 | Vacant | Not filled this term