The 2000 California State Senate elections were held on November 7, 2000. Senate seats of odd-numbered districts were up for election. Senate terms are staggered so that half the membership is elected every two years. Senators serve four-year terms and are limited to two terms. The Democratic Party held on to the majority of the seats, gaining one seat in the process.

The 1998 California State Senate elections were held on November 3, 1998. Senate seats of even-numbered districts were up for election. Senate terms are staggered so that half the membership is elected every two years. Senators serve four-year terms and are limited to two terms. Democrats expanded their majority, winning a Republican-held seat and an Independent-held seat.