| Election Name: | 2010 California State Senate election |
| Country: | California |
| Type: | legislative |
| Ongoing: | no |
| Previous Election: | 2008 California State Senate election |
| Previous Year: | 2008 |
| Next Election: | 2012 California State Senate election |
| Next Year: | 2012 |
| Seats For Election: | 20 seats from even-numbered districts in the California State Senate |
| Majority Seats: | 21 |
| Election Date: | November 2, 2010 |
| Image1: | File:Darrell Steinberg 2014 CADEM Convention.jpg |
| Leader1: | Darrell Steinberg |
| Party1: | California Democratic Party |
| Leaders Seat1: | 6th–Sacramento |
| Seats Before1: | 25 |
| Seats After1: | 25 |
| Popular Vote1: | 2,279,834 |
| Percentage1: | 55.57% |
| Leader2: | Robert Dutton |
| Party2: | California Republican Party |
| Leaders Seat2: | 31st–Rancho Cucamonga |
| Seats Before2: | 15 |
| Seats After2: | 15 |
| Popular Vote2: | 1,736,816 |
| Percentage2: | 42.33% |
| Map Size: | 450px |
| President pro tempore | |
| Posttitle: | President pro tempore-designate |
| Before Election: | Darrell Steinberg |
| Before Party: | California Democratic Party |
| After Election: | Darrell Steinberg |
| After Party: | California Democratic Party |
The 2010 California State Senate elections were held on November 2, 2010. Voters in the 20 even-numbered districts of the California State Senate voted for their representatives. Other elections were also held on November 2. No seats changed parties in this election.
| California State Senate elections, 2010 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Party | Votes | Percentage | Not up | Contested | Before | After | +/– | ||
| Democratic | 2,279,834 | 55.57% | 11 | 14 | 25 | 25 | |||
| Republican | 1,736,816 | 42.33% | 9 | 6 | 15 | 15 | |||
| Libertarian | 64,164 | 1.56% | 0 | 0 | 0 | 0 | |||
| American Independent | 11,871 | 0.29% | 0 | 0 | 0 | 0 | |||
| Peace and Freedom | 10,209 | 0.25% | 0 | 0 | 0 | 0 | |||
| Independent | 10 | 0.00% | 0 | 0 | 0 | 0 | |||
| Totals | 4,102,904 | 100.00% | 20 | 20 | 40 | 40 | — | ||
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Incumbent Jenny Oropeza died on October 20, 2010, from complications from a blood clot, and remained on the ballot. A special election was called after she posthumously won the election.