When uninsured Medicaid-eligible adults are compared with Medicaid-enrolled adults with the same health and demographic characteristics, the uninsured are more likely to report unmet need, to lack a usual source of care, and to make less use of physician services. Families of the uninsured are also more likely to be burdened with out-of-pocket health care costs. Medicaid-eligible adults with private health insurance coverage are less likely to report unmet medical needs than their Medicaid-enrolled counterparts, but they are more likely to be burdened by out-of-pocket health care costs. Research is based upon data from the 1997 National Health Interview Survey.