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 lost to Republican U.S. Representative Cory Gardner by a margin of 1.9 percent.