|- ! | Robert H. Michel | | Republican | 1956 | Incumbent re-elected. | nowrap | |- ! | Tom Railsback | | Republican | 1966 | Incumbent re-elected. | nowrap | |- ! | Paul Findley | | Republican | 1960 | Incumbent re-elected. | nowrap | |- ! | Edward Rell Madigan | | Republican | 1972 | Incumbent re-elected. | nowrap | |- ! | George E. Shipley | | Democratic | 1958 | Incumbent re-elected. | nowrap | |- ! | Melvin Price | | Democratic | 1944 | Incumbent re-elected. | nowrap | |- ! | Paul Simon | | Democratic | 1974 | Incumbent re-elected. | nowrap | |} Indiana |- ! | Ray Madden | | Democratic | 1942 | | Lost renominationDemocratic hold. | nowrap | |- ! | Floyd Fithian | | Democratic | 1974 | Incumbent re-elected. | nowrap | |- ! | John Brademas | | Democratic | 1958 | Incumbent re-elected. | nowrap | |- ! | J. Edward Roush | | Democratic | 19581968 1970 | | Lost re-electionRepublican gain. | nowrap | |- ! | Elwood Hillis | | Republican | 1970 | Incumbent re-elected. | nowrap | |- ! | David W. Evans | | Democratic | 1974 | Incumbent re-elected. | nowrap | |- ! | John T. Myers | | Republican | 1966 | Incumbent re-elected. | nowrap | |- ! | Philip H. Hayes | | Democratic | 1974 | | Incumbent retired to run for U.S. senator.New member elected.Democratic hold. | nowrap | |- ! | Lee H. Hamilton | | Democratic | 1964 | Incumbent re-elected. | nowrap | |- ! | Philip Sharp | | Democratic | 1974 | Incumbent re-elected. | nowrap | |- ! | Andrew Jacobs Jr. | | Democratic | 19641972 1974 | Incumbent re-elected. | nowrap | |} Iowa |- ! | Edward Mezvinsky | | Democratic | 1972 | | Lost re-electionRepublican gain. | nowrap | |- ! | Mike Blouin | | Democratic | 1974 | Incumbent re-elected. | nowrap | |- ! | Chuck Grassley | | Republican | 1974 | Incumbent re-elected. | nowrap | |- ! | Neal Edward Smith | | Democratic | 1958 | Incumbent re-elected. | nowrap | |- ! | Tom Harkin | | Democratic | 1974 | Incumbent re-elected. | nowrap | |-