| Incumbent re-elected. | nowrap | |- ! | Ambrose Jerome Kennedy | | Democratic | 1932 | | Incumbent lost renomination.New member elected.Democratic hold. | nowrap | |- ! | Lansdale Sasscer | | Democratic | 1939 | Incumbent re-elected. | nowrap | |- ! | William D. Byron | | Democratic | 1938 | Incumbent re-elected. | nowrap | |} Massachusetts |- ! | Allen T. Treadway | | Republican | 1912 | Incumbent re-elected. | nowrap | |- ! | Charles R. Clason | | Republican | 1936 | Incumbent re-elected. | nowrap | |- ! | Joseph E. Casey | | Democratic | 1934 | Incumbent re-elected. | nowrap | |- ! | Pehr G. Holmes | | Republican | 1930 | Incumbent re-elected. | nowrap | |- ! | Edith Nourse Rogers | | Republican | 1925 | Incumbent re-elected. | nowrap | |- ! | George J. Bates | | Republican | 1936 | Incumbent re-elected. | nowrap | |- ! | Lawrence J. Connery | | Democratic | 1937 | Incumbent re-elected. | nowrap | |- ! | Arthur D. Healey | | Democratic | 1932 | Incumbent re-elected. | nowrap | |- ! | Robert Luce | | Republican | 1936 | | Incumbent lost re-election.New member elected.Democratic gain. | nowrap | |- ! | George H. Tinkham | | Republican | 1914 | Incumbent re-elected. | nowrap | |- ! | Thomas A. Flaherty | | Democratic | 1937 | Incumbent re-elected. | nowrap | |- ! | John W. McCormack | | Democratic | 1928 | Incumbent re-elected. | nowrap | |- ! | Richard B. Wigglesworth | | Republican | 1928 | Incumbent re-elected. | nowrap | |- ! | Joseph W. Martin Jr. | | Republican | 1924 | Incumbent re-elected. | nowrap | |- ! | Charles L. Gifford | | Republican | 1922 | Incumbent re-elected. | nowrap | |} Michigan |- ! | Rudolph G. Tenerowicz | | Democratic | 1938 | Incumbent re-elected. | nowrap | |- ! | Earl C. Michener | | Republican | 1934 | Incumbent re-elected. | nowrap | |- ! | Paul W. Shafer | | Republican | 1936 | Incumbent re-elected. | nowrap | |- ! | Clare Hoffman | | Republican | 1934 | Incumbent re-elected. | nowrap | |- ! | Bartel J. Jonkman | |