- Democratic congressional and state primaries: mixed
- Republican congressional and state primaries: mixed
- Democratic Presidential primary: closed
- Republican Presidential primary: closed
- Optional party affiliation. Voters are given the option to affiliate or not to affiliate with a political party on the registration form.
- 33% of registered voters in Arizona are unaffiliated or independent.
Details of state and local primary elections:
- Unaffiliated voters may choose which party's ballot they will vote on.
- Party members may only vote on their party's ballot.
- Voter registration closes 29 days before the primary election.