| district | incumbent | party | first_elected | result | candidates |
| illinois 3 | robert p hanrahan | republican | 1972-01-01 | lost re - election democratic gain | marty russo (d) 52.6% robert p hanrahan (r) 47.4% |
| illinois 4 | ed derwinski | republican | 1958-01-01 | re - elected | ed derwinski (r) 59.2% ronald a rodger (d) 40.8% |
| illinois 6 | harold r collier | republican | 1956-01-01 | retired republican hold | henry hyde (r) 53.4% edward v hanrahan (d) 46.6% |
| illinois 9 | sidney r yates | democratic | 1964-01-01 | re - elected | sidney r yates (d) unopposed |
| illinois 10 | samuel h young | republican | 1972-01-01 | lost re - election democratic gain | abner j mikva (d) 50.9% samuel h young (r) 49.1% |
| illinois 12 | phil crane | republican | 1969-01-01 | re - elected | phil crane (r) 61.1% betty c spence (d) 38.9% |
| illinois 19 | tom railsback | republican | 1966-01-01 | re - elected | tom railsback (r) 65.3% jim gende (d) 34.7% |
| illinois 20 | paul findley | republican | 1960-01-01 | re - elected | paul findley (r) 54.8% peter f mack (d) 45.2% |
| illinois 23 | melvin price | democratic | 1944-01-01 | re - elected | melvin price (d) 80.5% scott randolph (r) 19.5% |