The 2006 United States Senate elections were held on November 7, 2006, with all 33 Class 1 Senate seats being contested. The term of office for those elected in 2006 ran from January 3, 2007, to January 3, 2013. Prior to the election, the Republican Party controlled 55 of the 100 Senate seats. The Senate elections were part of the Democratic sweep during the 2006 elections, in which Democrats made numerous gains and no congressional or gubernatorial seat held by a Democrat was won by a Republican. However, Democratic incumbent Joe Lieberman in Connecticut was defeated in the primary and was later reelected as a third party candidate; he continued to caucus with the Democrats. Because of this, this is the first time since 1970 in which a member of a third party, who is not an independent, was elected to the Senate. Independent Jim Jeffords in Vermont retired but was succeeded by another Independent, Bernie Sanders, retaining their presence in the Senate. Jeffords and Sanders both caucused with Democrats. Democrats picked up six seats, all via the defeats of incumbents, in Missouri, Montana, Pennsylvania, Ohio, Rhode Island, and Virginia; while holding open seats in Maryland and Minnesota. Republicans held their sole open seat in Tennessee. Following the elections, no party held a majority of seats for the first time since January 1955. The Democrats were able to control the chamber because the two Independents caucused with the Democrats. They needed at least 51 seats to control the Senate because Vice President Dick Cheney would have broken any 50–50 tie in favor of the Republicans. This was the only time between 1990 and 2022 that Democrats gained Senate seats in a midterm. , this was the last time Democrats won a Senate election in Nebraska and the last time they did not win a seat in Connecticut. Results summary Summary of the November 7, 2006, United States Senate election results Sources: Dave Leip's Atlas of U.S. Elections United States Elections Project at George Mason University Change in composition Before the elections After the elections Final pre-election predictions Race summary Special elections during the 109th Congress There were no special elections during the 109th Congress. Elections leading to the next Congress In these general elections, the winners were elected for the term beginning January 3, 2007; ordered by state. All of the elections involved the Class 1 seats. Closest races In