| State (class) Vacator Reason for change Successor Date of successor's formal installation | |
| Texas (2) William A. Blakley (D) Lost special election. Successor elected June 14, 1961. John Tower (R) June 15, 1961 | |
| New Hampshire (2) Styles Bridges (R) Died November 26, 1961. Successor appointed January 10, 1962. Maurice J. Murphy, Jr. (R) January 10, 1962 | |
| Kansas (2) Andrew F. Schoeppel (R) Died January 21, 1962. Successor appointed January 31, 1962, and then elected November 6, 1962. James B. Pearson (R) January 31, 1962 | |
| South Dakota (3) Francis H. Case (R) Died June 23, 1962. Successor appointed July 9, 1962 to finish the term. Joseph H. Bottum (R) July 9, 1962 | |
| Idaho (2) Henry Dworshak (R) Died July 23, 1962. Successor appointed August 6, 1962, and then elected November 6, 1962. Leonard B. Jordan (R) August 6, 1962 | |
| Wyoming (2) John J. Hickey (D) Lost special election. Successor elected November 6, 1962. Milward L. Simpson (R) November 6, 1962 | |
| Massachusetts (1) Benjamin A. Smith II (D) Successor elected November 6, 1962. Ted Kennedy (D) November 7, 1962 | |
| New Hampshire (2) Maurice J. Murphy, Jr. (R) Lost special election. Successor elected November 6, 1962. Thomas J. McIntyre (D) November 7, 1962 | |
| New Mexico (1) Dennis Chavez (D) Died November 18, 1962. Successor appointed November 30, 1962 to continue the term. Edwin L. Mechem (R) November 30, 1962 | |
| Oklahoma (2) Robert S. Kerr (D) Died January 1, 1963. Vacant Not filled this term | |