04/24/2026
What is a primary election?
A primary election determines which candidates will represent their political party in the general election.
Think of it as a two-stage process. In the first stage — the primary — members of each party vote to choose their party's nominee. The winners of each party's primary then face each other in the second stage — the general election — where all voters choose the final officeholder.
For example, if five Republicans and three Democrats all want to run for county commissioner, the primary narrows it down to one Republican nominee and one Democratic nominee, who then compete in November.
In primary elections, registered Republicans vote in the Republican primary and registered Democrats vote in the Democratic primary. Minor parties also hold a primary election if more than one candidate from their party runs for any particular office.
Colorado switched to a semi-open primary system when voters approved Proposition 108 in 2016, which allowed unaffiliated voters to vote in either the Democratic, Republican, or a minor party primary starting in 2018.
Colorado holds primary elections in June of even-numbered years, followed by the general election in November. This year, the primary election will take place on June 30, and the general election will be held on November 3.
