The elections to the United States Senate were held on November 6, 2018. 33 of the 100 seats were contested in regular elections and two seats in special elections. The winners of the 33 regular elections will serve six-year terms from January 3, 2019, to January 3, 2025. Democrats had 26 seats up for election, including the seats of two independents who caucus with them. Republicans had nine seats up for election. The seats up for regular election in 2018 were last up in 2012; in addition, special elections were scheduled due to vacancies in Minnesota and Mississippi.
Although the final tally is yet to be confirmed, the Republicans kept the Senate majority, defeating three Democratic incumbents in Indiana, Missouri, and North Dakota. This is the first midterm election cycle since 2002 where any incumbents of the non-presidential party lost re-election. Democrats defeated a Republican incumbent in Nevada and gained an open seat in Arizona. Out of the 33 determined winners, 22 are Democrats, nine are Republicans, and two are independents who caucus with the Democrats. The winner in Florida and the Mississippi runoff election have yet to be determined.