| Election Name: | 1948 United States Senate election in Illinois |
| Country: | Illinois |
| Flag Year: | 1915 |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1942 United States Senate election in Illinois |
| Previous Year: | 1942 |
| Next Election: | 1954 United States Senate election in Illinois |
| Next Year: | 1954 |
| Election Date: | November 2, 1948 |
| Nominee1: | Paul Douglas |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 2,147,754 |
| Percentage1: | 55.07% |
| Nominee2: | Charles W. Brooks |
| Party2: | Republican Party (United States) |
| Popular Vote2: | 1,740,026 |
| Percentage2: | 44.61% |
| Map Size: | 300x300px |
| U.S. Senator | |
| Before Election: | Charles W. Brooks |
| Before Party: | Republican Party (United States) |
| After Election: | Paul Douglas |
| After Party: | Democratic Party (United States) |
The 1948 United States Senate election in Illinois took place on November 2, 1948. Incumbent Republican Charles W. Brooks lost reelection in the landslide to Democrat Paul Douglas.
The primaries and general election coincided with those of other federal elections (United States President and House), as well as those for state elections.
Primaries were held April 13, 1948.