This report focuses on Medicaid and the State Children's Health Insurance Program (SCHIP) for low-income, uninsured children. It presents data from the 1999 National Survey of America's Families (NSAF), which indicated that 72 percent of eligible children without any other coverage were covered by Medicaid in 1999, leaving over 4 million Medicaid-eligible children uninsured. Children with greater health services needs participated in Medicaid/SCHIP at higher rates than other children. There was variation in Medicaid and SCHIP participation among children in different racial/ethnic subgroups. Children were less likely to participate when their families had not previously been enrolled in welfare. (Contains 12 references.) (SM)