Mark Udall Democratic Cory Gardner Republican The 2014 United States Senate election in Colorado was held on November 4, 2014, to elect a member of the United States Senate to represent the State of Colorado, concurrently with the election of the Governor of Colorado, other elections to the United States Senate, elections to the United States House of Representatives, and various state and local elections.

Incumbent Democratic Senator Mark Udall ran for re-election to a second term, but narrowly lost to Republican U.S. Representative Cory Gardner by a margin of 1.9 percent.

As of 2025, this is the last time that a Republican has won a Senate election in the state.

[1] At the Republican state assembly on April 12, 2014, Cory Gardner received 73% of the votes of over 3,900 delegates.

[4] Individuals Newspapers [112] Counties that flipped from Democratic to Republican Gardner won 4 of 7 congressional districts.