The California Science and Engineering Fair (or CSEF), previously known as the California State Science Fair, is a science fair held annually in Los Angeles, California. It serves as the final science fair of the academic year and is a feeder competition to the International Science and Engineering Fair (ISEF) and the Thermo Fisher Junior Innovators Challenge (TFJIC). First established in 1952, CSEF was designated the state's official science fair in 1990 and ran its 74th fair in 2025.
Every year, roughly 900 students from middle schools and high schools across California compete across two divisions and eighteen categories for the chance to win over $30,000 in prizes.
No fair was held in 2020 as officials cited the COVID-19 pandemic as grounds for cancellation. The 69th was deferred to 2021.
The fair is fed by 28 regional science fairs, each of which is allocated a number of projects based on their number of participants. Projects can qualify by either placing first or second in their category at these fairs. The allocation in 2009 was 908 projects, an average of 24.7 projects per million population.
Awards, given in several categories across both divisions, are posted shortly after the fair ends each year. Roughly two to three projects amongst the first-place Senior division category winners are chosen to advance to ISEF.
At the 2009 fair, major awards included the Patricia Beckman Project of the Year AwardâÂÂDavid Zarrin of Redwood Middle School, Saratoga won the Junior Division ($5,000 award) and Anna K. Simpson of Patrick Henry Senior High School, San Diego won the Senior Division ($10,000). There are also many special awards sponsored by various organizations, some with cash prizes.