|-! | Thomas R. Underwood| | Democratic| 1948| | Incumbent resigned March 17, 1951 when appointed U.S. Senator.
New member elected April 4, 1951.
Democratic hold.| nowrap |
|-! | John Kee| | Democratic| 1932| | Incumbent died May 8, 1951.
New member elected July 17, 1951 (see Widow's succession).
Democratic hold.| nowrap |
|-! | Frank Buchanan| | Democratic| nowrap | 1946 (special)| | Incumbent died April 27, 1951.
New member elected July 24, 1951.
Democratic hold.| nowrap |
|-! | Frank Fellows| | Republican| 1940| | Incumbent died April 27, 1951.
New member elected October 22, 1951.
Republican hold.| nowrap |
|-! | Harry L. Towe| | Republican| 1942| | Incumbent resigned September 7, 1951 to become N.J. Assistant Attorney General.
New member elected November 6, 1951.
Republican hold.| nowrap |
|-! | Edward G. Breen| | Democratic| 1948| | Incumbent resigned October 1, 1951, due to ill health.
New member elected November 6, 1951.
Republican gain.| nowrap |
|-! | Wilson D. Gillette| | Republican| nowrap | 1941 (special)| | Incumbent died August 7, 1951.
New member elected November 6, 1951.
Republican hold.| nowrap |
|-! | Albert C. Vaughn| | Republican| 1950| | Incumbent died September 1, 1951.
New member elected November 6, 1951.
Republican hold.| nowrap |
|-! | Karl Stefan| | Republican| 1934| | Incumbent died August 7, 1951.
New member elected December 4, 1951.
Republican hold.| nowrap | |}