"Unvaccinated children are the highest risk for measles and death," said a supporter of the bill.
The bill approved Thursday would prohibit parents from seeking vaccine exemptions for their children because of religious or personal beliefs.
SB277 by Democratic senators Ben Allen of Santa Monica and Richard Pan of Sacramento would make medical waivers available only for children who have health problems, forcing unvaccinated children to be home schooled.
"Together we are turning the tide to stop communicable diseases before any more families are hurt," said Senator Pan.
Red-shirted opponents, some with fussy children, crowded the public gallery to watch the nearly hour-long Senate debate.
"As parents we have the right to choose what is best for our children, no matter what it is," said Jeannie Emmett.
Many opponents, though, have concerns over what they believe is a link between vaccinations and autism. It's a connection that has not been supported by scientific evidence.
"I don't feel like many people are truly anti-vaccine, rather I feel like they worried more about their religious rights and personal rights being trampled," said a demonstrator.
The American Association of Pediatrics and the California Medical Association both said the benefits of vaccines far outweigh any risks.
"Together we are turning the tide to stop communicable diseases before any more families are hurt," said Senator Richard Pan.California Senator Richard Pan, who proposed SB277, is a practicing pediatrician, and has received death threats by some of his critics.
"Some of the opponents have unfortunately engaged in hate and bullying. That is not how we should make public policy," he said.
Senators approved the measure on a 25-10 vote, sending it to the Assembly. Gov. Jerry Brown has not taken a position on the bill.
California would join Mississippi and West Virginia as the only states with such strict requirements if the bill becomes law.