The 1934 United States elections were held on November 6, 1934. The election took place in the middle of Democratic President Franklin D. Roosevelt's first term, during the Great Depression. The Democrats built on the Congressional majorities they had won in the previous two elections. In the House of Representatives, Roosevelt's party gained nine seats, mostly from the Republican Party. The Democrats also gained nine seats in the U.S. Senate, thereby winning a supermajority. A Progressive also unseated a Republican in the Senate. This marked the first time since the Civil War that an incumbent president's party gained seats in a midterm election, followed by 1998 and 2002.
The election was perhaps the most successful midterm of the 20th century for the party in control of the presidency. Despite opposition from Republicans, business organizations such as the US Chamber of Commerce, and disaffected Democrats who formed the American Liberty League, Roosevelt's New Deal policies were bolstered and his New Deal coalition was solidified. The election was critical in re-centering the Democratic Party in Northern, urban areas, as opposed to the party's traditional base in the South. Conservative Republicans also suffered major losses across the country. Future president Harry S. Truman won election as Senator from Missouri during this election.