The 1878 United States general election occurred in the middle of Republican President Rutherford B. Hayes's term, during the Third Party System. Members of the 46th United States Congress were chosen in this election. Democrats won control of the Senate for the first time since the start of the Civil War. Democrats lost a majority in the House, but retained a plurality and control of the chamber.
In the House, Democrats and Republicans both lost seats to the Greenback Party and a group of independent Democrats, with the Democrats retaining only a plurality. Democrat Samuel J. Randall won re-election as Speaker of the House.
In the Senate, Democrats picked up several seats, taking control of the chamber.