The San Joaquin County Registrar of Voters Office is a division of the County Administrator's office and is responsible for conducting fair, impartial, accurate, secure and transparent federal, state and local elections. Other functions of the Registrar of Voters Office include voter registration, election administration and campaign finance disclosures.

As of June 7, 2022, San Joaquin County has 385,040 active registered voters of an estimated population of 432,516 eligible voters. It takes about 900 people to conduct a countywide election, including county staff, election officers and election night workers.