Incumbent Democratic senator Tammy Duckworth was re-elected for a second term against former U.S. House of Representatives candidate Kathy Salvi, the Republican nominee, winning by a margin of 15.3%, 0.2% more than her 2016 margin.

This was the first Illinois U.S. Senate election where both major party candidates were female.

Salvi flipped seven counties—Calhoun, McDonough, Knox, Gallatin, Pulaski, Alexander, and Madison—that had voted for Duckworth in 2016.

On the other hand, Duckworth won Kendall, McLean, Peoria, and Winnebago, which had all voted against her in 2016.

Senators Labor Unions Organizations Newspapers U.S. Executive Branch officials State legislators Local officials Newspapers Organizations Aggregate polls Graphical summary Tammy Duckworth vs. generic opponent Democratic Republican Other parties Duckworth won 14 of 17 congressional districts.