That's up from 46 percent who cited obesity as a central concern in 2003, the last time the question was posed.
A third of those polled blame unhealthy eating habits and too much fast food. Another 15 percent said the real culprit in childhood obesity is a lack of physical activity.
Nearly half of all polled said the average child is eating less fruits and vegetables and other healthy foods than they were five years ago.
The telephone survey of 1,005 California voters was conducted in October, and was funded by The California Endowment. The poll has a margin of error of plus or minus 3.2 percentage points.