This report from the UCLA Center for Health Policy Research shows that job-based health insurance coverage -- the backbone of the state's system of health insurance -- is declining. More than 6.6 million Californians under age 65 (more than one in five nonelderly residents) went without insurance for at least part of 2003 and more than 3.7 million lacked health coverage for the entire year. While a majority of Californians are still insured through their jobs or those of relatives, those numbers are declining, specifically among dependents. Pushed by a dramatic 79.1 percent increase in the cost of job-based family coverage for the average worker, enrollment of dependents dropped 4 percentage points for children and 2 percentage points for adults from 2001 to 2003. All income groups and all racial and ethnic groups had significant decreases in job-based insurance. Among children, however, these losses were balanced by a 5 percentage point increase in children's enrollment in Medi-Cal and Healthy Families, leading to an actual increase in children's insurance overall. Other findings from the report include: Nonelderly Latinos and American Indian/Alaska Natives report highest rates of uninsurance. Three out of four uninsured are in working families. Two-thirds of children in Medi-Cal or Healthy Families had at least one parent who was employed. Main reason the uninsured give for not having coverage is "I can't afford it." Those without health insurance were much less likely to have seen a doctor, get vital preventive screenings for cancer, or take medication for high blood pressure.