In August 2019, it was revealed that Hickenlooper ended his presidential bid to run for the United States Senate in 2020 against incumbent Senator Cory Gardner. In a poll for potential Democratic candidates for the Colorado Senate, Hickenlooper was the front-runner with 61%. On August 22, 2019, Hickenlooper announced his candidacy for the Senate. In June 2020, he won the Democratic nomination. On November 3, 2020, Hickenlooper was declared the winner of the Senate race. 