The U.S. Senate election, 1964 was an election for the United States Senate which coincided with the re-election of President Lyndon Baines Johnson by an overwhelming majority. His Democratic Party picked up a net two seats from the Republicans. As of 2004, this is the last time either party has had a two-thirds majority in the Senate, although with a Democratic president the ability to override a veto or impeach a President was not particularly relevant.

Democrats defeated Republican incumbents Edwin L. Mechem (R-NM), Kenneth B. Keating (R-NY), and James Glenn Beall (R-MD), while Republicans defeated incumbent Pierre Salinger (D-CA).

Notable freshmen included future Vice President and presidential candidate Walter Mondale (D-MN), appointed to the seat left vacant by newly elected Vice President Hubert H. Humphrey, and future presidential candidate Robert F. Kennedy (D-NY), former attorney general and brother of the assassinated President John F. Kennedy.

In 1966, Republican Robert P. Griffin was appointed to the vacancy left by the death of Patrick V. McNamara (D-MI). This is not reflected in the party balances below.

Senate contests in 1964

State	Incumbent	Party	Status	Opposing Candidates
Arizona	Barry Goldwater	Republican	Retired: Republican victory, 51.4 - 48.6	Paul Fannin (Republican) Roy Elson (Democrat)
California	Pierre Salinger	Democrat	Defeated, 51.5 - 48.5	George Murphy (Republican)
Connecticut	Thomas J. Dodd	Democrat	Re-elected, 64.6 - 35.3	John Lodge (Republican)
Delaware	John J. Williams	Republican	Re-elected, 51.7 - 48.3	Elbert N. Carvel (Democrat)
Florida	Spessard L. Holland	Democrat	Re-elected, 63.9 - 36.0	Claude R. Kirk, Jr. (Republican)
Hawaii	Hiram L. Fong	Republican	Re-elected, 53.0 - 46.4	Thomas P. Gill (Democrat)
Indiana	Vance Hartke	Democrat	Re-elected, 54.3 - 45.3	D. Russell Bontrager (Republican)
Maine	Edmund S. Muskie	Democrat	Re-elected, 66.6 - 33.4	Clifford G. McIntyre (Republican)
Maryland	James Glenn Beall	Republican	Defeated, 62.8 - 37.2	Joseph D. Tydings (Democrat)
Massachusetts	Edward M. Kennedy	Democrat	Re-elected, 74.3 - 25.4	Howard Whitmore, Jr. (Republican)
Michigan	Philip A. Hart	Democrat	Re-elected, 64.4 - 35.3	Elly M. Petersen (Republican)
Minnesota	Eugene J. McCarthy	Democrat	Re-elected, 60.3 - 39.3	Wheelock Whitney (Republican)
Mississippi	John C. Stennis	Democrat	Re-elected, unopposed
Missouri	Stuart Symington	Democrat	Re-elected, 66.6 - 33.4	Jean P. Bradshaw (Republican)
Montana	Mike Mansfield	Democrat	Re-elected, 64.5 - 35.5	Alex Blewett (Republican)
Nebraska	Roman L. Hruska	Republican	Re-elected, 61.4 - 38.6	Raymond W. Arndt (Democrat)
Nevada	Howard W. Cannon	Democrat	Re-elected, 50.0 - 50.0	Paul Laxalt (Republican)
New Jersey	Harrison A. Williams, Jr.	Democrat	Re-elected, 61.9 - 37.3	Bernard M. Shanley (Republican)
New Mexico	Edwin L. Mechem	Republican	Defeated, 54.7 - 45.3	Joseph M. Montoya (Democrat)
New York	Kenneth B. Keating	Republican	Defeated, 53.5 - 43.4	Robert F. Kennedy (Democrat)
North Dakota	Quentin N. Burdick	Democrat	Re-elected, 57.6 - 42.4	Thomas S. Kleppe (Republican)
Ohio	Stephen M. Young	Democrat	Re-elected, 50.2 - 49.8	Robert A. Taft, Jr. (Republican)
Oklahoma1	James H. Edmondson	Democrat	Defeated in primary: Democrat victory, 51.2 - 48.8	Fred R. Harris (Democrat) Bud Wilkinson (Republican)
Pennsylvania	Hugh Scott	Republican	Re-elected, 50.6 - 49.1	Genevieve Blatt (Democrat)
Rhode Island	John O. Pastore	Democrat	Re-elected, 82.7 - 17.3	Ronald R. Lagueux (Republican)
Tennessee	Albert Gore, Sr.	Democrat	Re-elected, 53.6 - 46.4	Dan H. Kuykendall (Republican)
Tennessee2	Herbert S. Walters	Democrat	Retired: Democrat victory, 52.1 - 47.4	Ross Bass (Democrat) Howard H. Baker, Jr. (Republican)
Texas	Ralph Yarborough	Democrat	Re-elected, 56.2 - 43.6	George H. W. Bush (Republican)
Utah	Frank E. Moss	Democrat	Re-elected, 57.3 - 42.7	Ernest L. Wilkinson (Republican)
Vermont	Winston L. Prouty	Republican	Re-elected, 53.5 - 46.5	Frederick J. Fayette (Democrat)
Virginia	Harry F. Byrd	Democrat	Re-elected, 63.8 - 19.0 - 10.3	Richard A. May (Republican) James W. Respess (Independent)
Washington	Henry M. Jackson	Democrat	Re-elected, 72.2 - 27.8	Lloyd J. Andrews (Republican)
West Virginia	Robert C. Byrd	Democrat	Re-elected, 67.7 - 32.3	Cooper P. Benedict (Republican)
Wisconsin	William Proxmire	Democrat	Re-elected, 53.3 - 46.6	Wilbur N. Renk (Republican)
Wyoming	Gale McGee	Democrat	Re-elected, 54.0 - 46.0	John S. Wold (Republican)

¹ special election held due to death of Robert S. Kerr (D-OK)

² special election held due to death of Estes Kefauver (D-TN)

See also

• U.S. Senate election, 1962
• U.S. Senate election, 1966
• U.S. presidential election, 1964
• U.S. House election, 1964

Senate composition before and after elections

88th Congress Senate Composition

89th Congress Senate Composition

Color Key: Democrats Republicans