State (class) | Vacator | Reason for change | Successor | Date of successor's formal installation
--- | --- | --- | --- | ---
New Jersey (1) | William Warren Barbour (R) | Died November 22, 1943. Successor was appointed until an election. | Arthur Walsh (D) | November 26, 1943
Indiana (3) | Frederick Van Nuys (D) | Died January 25, 1944. Successor was appointed until an election. | Samuel D. Jackson (D) | January 28, 1944
Massachusetts (2) | Henry Cabot Lodge, Jr. (R) | Resigned February 3, 1944, to go on active duty in the US Army. Success was appointed until a special election. | Sinclair Weeks (R) | February 8, 1944
Oregon (2) | Charles L. McNary (R) | Died February 25, 1944. Successor was appointed and subsequently won special election | Guy Cordon (R) | March 4, 1944
Washington (3) | Homer Bone (D) | Resigned November 13, 1944, to become Judge of the U.S. Court of Appeals for the 9th Circuit. | Warren Magnuson (D) | December 14, 1944
Indiana (3) | Samuel D. Jackson (D) | Appointee was not a candidate to finish the term. Successor was elected. | William E. Jenner (R) | November 7, 1944
South Carolina (3) | Ellison Durant Smith (D) | Died November 17, 1944. | Wilton E. Hall (D) | November 20, 1944
New Jersey (1) | Arthur Walsh (D) | Appointee was not a candidate to finish the term. Successor was elected. | H. Alexander Smith (R) | December 7, 1944
Massachusetts (2) | Sinclair Weeks (R) | Appointee was not a candidate to finish the term. Successor was elected. | Leverett Saltonstall (R) | January 4, 1945