| Election Name: | 2004 California State Senate election |
| Country: | California |
| Type: | legislative |
| Ongoing: | no |
| Previous Election: | 2002 California State Senate election |
| Previous Year: | 2002 |
| Next Election: | 2006 California State Senate election |
| Next Year: | 2006 |
| Seats For Election: | 20 seats from odd-numbered districts in the California State Senate |
| Majority Seats: | 21 |
| Leader1: | John Burton |
| Party1: | California Democratic Party |
| Leaders Seat1: | 3rd–San Francisco |
| Last Election1: | 25 |
| Seats1: | 25 |
| Popular Vote1: | 3,419,002 |
| Percentage1: | 53.78% |
| Leader2: | Dick Ackerman |
| Party2: | California Republican Party |
| Leaders Seat2: | 33rd–Irvine |
| Last Election2: | 15 |
| Seats2: | 15 |
| Popular Vote2: | 2,702,511 |
| Percentage2: | 42.51% |
| Map Size: | 450px |
| President pro tempore | |
| Before Election: | John L. Burton |
| Before Party: | California Democratic Party |
| After Election: | Don Perata |
| After Party: | California Democratic Party |
The 2004 California State Senate elections were held on November 2, 2004. 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. As was expected, the Democratic Party held on to the majority of the seats.
| California State Senate elections, 2004 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Party | Votes | Percentage | Not up | Incumbents | Open | Before | After | ||
| Democratic | 3,419,002 | 53.78% | 14 | 6 | 5 | 25 | 25 | ||
| Republican | 2,702,511 | 42.51% | 6 | 4 | 5 | 15 | 15 | ||
| Libertarian | 201,249 | 3.17% | 0 | 0 | 0 | 0 | 0 | ||
| Peace and Freedom | 17,412 | 0.27% | 0 | 0 | 0 | 0 | 0 | ||
| Green | 16,644 | 0.26% | 0 | 0 | 0 | 0 | 0 | ||
| Totals | 6,356,818 | 100.00% | 20 | 10 | 10 | 40 | 40 | ||
Final results from the California Secretary of State:[1]
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