Democratic incumbent: Dick Durbin
Republican candidate: Steve Sauerberg
Durbin, 63, has been in the Senate since 1997, and has been Senate Democratic whip (second in line in the party leadership after the majority leader) since 2005. He served in the U.S. House from 1983 to 1997.
Sauerberg, 55, is a physician.
Real Clear Politics shows polls giving Durbin a substantial lead (28 points in the latest poll).
Illinois has traditionally been a battleground state, but has been reliably Democratic in the recent past. Barack Obama holds its other Senate seat.
This election is considered safe for the Democrats.