Missouri Elections and Voting: Registration, Primaries, and General Elections

Missouri's election system encompasses voter registration requirements, primary election structures, and general election procedures governed by state statute and administered through a network of 116 local election authorities. The Missouri Secretary of State serves as the state's chief election official, setting administrative standards and certifying results. This page covers the structural framework, procedural mechanics, and jurisdictional scope of Missouri elections as defined under Missouri Revised Statutes (RSMo) Chapter 115.

Definition and scope

Missouri elections operate under a bifurcated administrative model: the Missouri Secretary of State's office maintains statewide oversight, while 116 county and city election authorities — typically county clerks or boards of election commissioners — conduct actual voter registration, polling place operations, and vote tabulation at the local level.

Scope and coverage: This page addresses state-administered elections under Missouri jurisdiction, including federal, statewide, and general assembly contests. Local special district elections, municipal elections operating under separate charter authority (such as Kansas City and St. Louis City), and school board elections held on non-standard calendars fall under overlapping but distinct procedural frameworks. Federal election law — including regulations enforced by the U.S. Election Assistance Commission and provisions of the Help America Vote Act of 2002 — applies concurrently but is not covered in full here. Missouri ballot initiatives and referendums are addressed separately from the candidate-election procedures described on this page.

How it works

Voter registration

Missouri requires voters to register at least 28 days before an election (RSMo §115.135). Registration is available through:

Online registration via the Missouri Secretary of State portal
Paper forms submitted to local election authorities
In-person registration at motor vehicle licensing offices under the National Voter Registration Act of 1993
In-person registration at military recruitment offices and public assistance agencies

Registrants must be U.S. citizens, Missouri residents, and at least 18 years of age on or before election day. Missouri does not permit same-day voter registration. Photo identification is required at the polls under Missouri law (RSMo §115.427); acceptable forms include Missouri driver's licenses, state-issued non-driver IDs, military IDs, and U.S. passports.

Primary elections

Missouri conducts partisan primary elections to select candidates for the general election ballot. Missouri operates a closed primary for presidential preference contests but an open primary for all other offices — voters do not register by party and may select any single party's ballot on primary election day.

Missouri primaries for statewide and federal offices are held on the first Tuesday after the first Monday in August in even-numbered years (RSMo §115.123). Presidential preference primary elections are held separately, typically in March of presidential election years, as set by the General Assembly.

Primary vs. General Election: Key distinctions

Feature	Primary Election	General Election
Purpose	Nominate party candidates	Elect officeholders
Ballot selection	Voter chooses one party's ballot	All candidates appear on single ballot
Held	First Tuesday after first Monday in August	First Tuesday after first Monday in November
Threshold to advance	Plurality within party	Plurality statewide or by district

General elections

Missouri general elections are held on the first Tuesday after the first Monday in November in even-numbered years for federal and statewide offices, with gubernatorial elections occurring in years divisible by 4 in non-presidential cycles. Missouri uses a plurality voting system — the candidate with the highest vote count wins regardless of whether a majority is achieved. The state does not use ranked-choice voting or runoff elections for statewide offices.

Absentee voting is permitted for any registered voter who meets one of the statutory qualifying reasons enumerated in RSMo §115.277, including absence from the county, illness, religious observance, or service as an election judge. Missouri does not offer universal no-excuse absentee voting for standard elections, though certain statutory modifications have applied in specific election cycles as enacted by the General Assembly.

Common scenarios

Scenario 1 — Voter who has moved within Missouri: A registered voter who relocates within the state must update their registration with the new county election authority. Registration in the prior county remains valid through the 28-day cutoff for the next election but does not transfer automatically.

Scenario 2 — Candidate filing for state legislative office: Candidates for the Missouri General Assembly file declaration of candidacy forms with the Missouri Secretary of State's office during a statutory filing period, generally held in February of election years. Filing fees vary by office; candidates may alternatively submit a petition with the required number of qualifying signatures in lieu of a fee.

Scenario 3 — Contested primary in a partisan race: If a primary produces a tie, Missouri statute provides for a coin toss or lot-drawing administered by the relevant election authority to determine the nominee, as specified under RSMo §115.507.

Decision boundaries

Missouri election administration intersects with legislative redistricting, which affects the geographic boundaries of all state legislative and congressional districts. Missouri redistricting and legislative districts are governed by separate constitutional provisions and are not determined by election authorities.

The Missouri Constitution establishes term limits for statewide offices: governors, lieutenant governors, secretaries of state, state auditors, state treasurers, and attorneys general are each limited to 2 four-year terms (Missouri Constitution, Article IV, §17). Missouri Senate members are limited to 2 four-year terms; Missouri House members are limited to 4 two-year terms (Missouri Constitution, Article III, §8).

Election disputes, including candidate eligibility challenges and recount petitions, are adjudicated through the Missouri circuit courts and, on appeal, through the Missouri Court of Appeals or the Missouri Supreme Court, depending on the nature and jurisdictional level of the contest.

The full landscape of Missouri government services — of which elections are one structural component — is mapped at Missouri Government Authority.