2014 United States Senate election in Colorado

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.

Despite Gardner's win however, with slightly over 48% of the vote, it is the lowest a winning Republican had received in the Class 2 Senate seat since 1918.

As of 2024, this is the last time that a Republican has won a Senate election in the state.

Democratic primary
Mark Udall was the only Democrat to file to run, and thus at the Democratic state assembly on April 12, 2014, he was renominated unopposed.

Nominee

 * Mark Udall, incumbent U.S. Senator

Republican primary
At the Republican state assembly on April 12, 2014, Cory Gardner received 73% of the votes of over 3,900 delegates. Neither Randy Baumgardner nor Tom Janich received the required 30% make the ballot and thus Gardner received the party's nomination.

Nominee

 * Cory Gardner, U.S. Representative

Rejected in convention

 * Randy Baumgardner, state senator
 * Tom Janich, perennial candidate

Withdrew

 * Mark Aspiri, businessman
 * Ken Buck, Weld County District Attorney and nominee for the U.S. Senate in 2010 (running for CO-04)
 * Owen Hill, state senator
 * Jaime McMillan, businessman
 * Amy Stephens, state representative
 * Floyd Trujillo, businessman

Declined

 * Bob Beauprez, former U.S. Representative and nominee for Governor in 2006 (running for Governor)
 * Mike Coffman, U.S. Representative
 * Dan Domenico, Solicitor General of Colorado
 * Doug Lamborn, U.S. Representative
 * Jane E. Norton, former lieutenant governor of Colorado and candidate for the U.S. Senate in 2010
 * Scott Renfroe, state senator
 * Victor E. Renuart Jr., former commander of United States Northern Command and the North American Aerospace Defense Command
 * Ellen Roberts, state senator
 * John Suthers, Attorney General of Colorado
 * Scott Tipton, U.S. Representative

Nominated

 * Gaylon Kent, candidate for Colorado's 3rd congressional district in 2012

Nominated

 * Bill Hammons, founder and National Chairman of the Unity Party of America

Declared

 * Raúl Acosta, IT professional
 * Steve Shogan, neurosurgeon

Debates

 * Complete video of debate, October 6, 2014
 * Complete video of debate, October 15, 2014

Counties that flipped from Democratic to Republican

 * Chaffee (largest municipality: Salida)
 * Conejos (largest municipality: Manassa)
 * Garfield (largest municipality: Rifle)
 * Grand (largest municipality: Granby)
 * Larimer (largest municipality: Fort Collins)
 * Las Animas (largest municipality: Trinidad)
 * Mineral (largest municipality: Creede)

By congressional district
Gardner won 4 of 7 congressional districts.