There have been 28 reported cases this year alone, officials said, and of those, 16 people reported recent international travel before getting the highly contagious illness.
Of the 28 cases of measles reported this year, 22 people were either unvaccinated or their vaccination status is unknown, according to a state health department spokesman.
Experts believe the recent outbreaks of measles in Europe and South Asia are contributing to the jump in the number of cases in California.
Symptoms include fever, followed by cough, runny nose and pink eye, and then the telltale rash sets in.
Experts advise that you are planning to travel to Europe or Asia anytime soon, you and your family should get vaccinated for measles.
There is not much concern in the public-health community about catching measles if you're traveling in Central or South America.
The Associated Press contributed to this report.