1958 United States Senate elections

1958 United States Senate elections

← 1956 November 4, 1958[a] 1960 →
← 1957 (TX, WI) 1959 (HI) →
36 of the 98 seats in the United States Senate 50 seats needed for a majority
Majority party Minority party   Leader Lyndon Johnson William Knowland (retired) Party Democratic Republican Leader since January 3, 1953 August 4, 1953 Leader's seat Texas California Seats before 49 47 Seats after 64 34 Seat change 15 13 Popular vote 21,426,124[1][b] 16,622,338[1] Percentage 55.3% 42.9% Seats up 13 21 Races won 28 8
Results of the elections:      Democratic gain      Democratic hold      Republican hold      No election Rectangular inset (Alaska and W. V.): both seats up for election
Majority Leader before election Lyndon Johnson Democratic Elected Majority Leader Lyndon Johnson Democratic

The 1958 United States Senate elections were elections for the United States Senate which occurred in the middle of President Dwight D. Eisenhower's second term. Thirty-two seats of Class 1 were contested in regular elections, the new state of Alaska held its first Senate elections for its Class 2 and 3 seats, and two special elections were held to fill vacancies.

As is common in mid-term elections, the party in the White House lost seats, but losses this year were heavy due to the Recession of 1958, the Eisenhower Administration's position on right-to-work issues that galvanized labor unions which supported Democrats, and the launch of Sputnik. This was the first time since 1934 that Democrats gained seats in this class of Senators. Democrats won both seats in West Virginia, making the last time that Democrats simultaneously flipped both of a state's Senate seats until Georgia's elections in 2020 and 2021.

The Democratic Party gained a record 15 seats in this election, defeating 10 Republican incumbents, gaining three open Republican seats, and winning both seats from the new state of Alaska. This gave the Democrats a strong Senate majority of 64–34 over the Republicans, and the largest swing in the history of the Senate. After the new state of Hawaii elected its first Senators in 1959, the Senate's balance changed to 65–35.

This is only one of two occasions in U.S. history that 10 or more Senate seats changed hands in a mid-term election (the other being in 1946), and also one of five occasions where 10 or more Senate seats changed hands in an election, with the other occasions being in 1920, 1932, 1946, and 1980.

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