United States Senate elections, 1958 Senate composition before the elections Senate composition before the elections

| D_48 | D_47 | D_46 | D_45 | D_44 | D_43 | D_42 | D_41 |
|---|---|---|---|---|---|---|---|
| D 9 | D 10 | D 11 | D 12 | D 13 | D 14 | D 15 | D 16 |
| D 28 | D 27 | D 26 | D 25 | D 24 | D 23 | D 22 | D 21 |
| D 29 | D 30 | D 31 | D 32 | D 33 | D 34 | D 35 | D 36 |
| D 48 | D 47 | D 46 | D 45 | D 44 | D 43 | D 42 | D 41 |
| D 49 | ← Majority | ← Majority | ← Majority | ← Majority | ← Majority | ← Majority | ← Majority |
| D 49 | R 47 | R 46 | R 45 | R 44 | R 43 | R 42 | R 41 |