The 2018 United States Senate election in Missouri took place on November 6, 2018, to elect a member of the United States Senate to represent the State of Missouri, concurrently with other elections to the United States Senate, elections to the United States House of Representatives, and various state and local elections, including Missouri's quadrennial State Auditor election.
This was one of ten Democratic-held Senate seats up for election in a state Donald Trump won in the 2016 presidential election. Incumbent Democratic Senator Claire McCaskill ran for re-election to a third term. McCaskill easily won her party's nomination, defeating several minor candidates in the primary, while Missouri Attorney General Josh Hawley comfortably won the Republican primary.
The candidate filing deadline was March 27, 2018, and the primary election was held on August 7, 2018. Pollsters predicted a tight race; however, Hawley defeated McCaskill on election day by 5.8%, taking 51.4% of the vote to McCaskill's 45.6%, a somewhat larger margin than expected. This resulted in Republicans holding both Senate seats in Missouri for the first time since McCaskill took office in 2007. Hawley was also the youngest incumbent senator at that time, and continued to be until the inauguration of Jon Ossoff in 2021. Despite her loss, McCaskill outperformed Hillary Clinton's performance in the state in the 2016 presidential race. This is the last U.S. Senate race in Missouri where the incumbent was defeated.
with Austin Petersen<br />
with generic Republican<br />
with Vicky Hartzler<br />
with Blaine Luetkemeyer<br />
with Todd Richardson<br />
with Eric Schmitt<br />
with Jason Smith<br />
Senator McCaskill conceded a few hours after the polls closed on election day. Despite performing strongly in the St. Louis suburbs, she ran well behind her 2012 vote in Southeast Missouri, especially in the Lead Belt and the Missouri Bootheel. She also ran poorly in the northern part of the state.
Hawley won five of eight congressional districts, with the remaining three going to McCaskill, including one that elected a Republican.
Official campaign websites