Health insurance is one of the essential enabling resources to gain access to medical care and ultimately increase health status. Over 11 million or one quarter of the nation's uninsured individuals are eligible for Medicaid or the State Children's Health Insurance Program (SCHIP), but are not enrolled. Interviews with 368 individuals from 1999 through 2003 identify eight primary barriers to enrollment in public insurance. These include: economic aspects of qualifying, lack of knowledge, benefit design of public programs, poor experiences and stigma, complexity and literacy, immigration status, poor customer service, and fear of fraud. These results suggest policy options alone are unlikely to result in reaching eligible uninsured individuals unless knowledge and instrumental support are offered to them about insurance. (Contains 1 table and 1 figure.)