Meeting the health needs of adolescents who live in high-risk settings such as homeless shelters, migrant camps, juvenile detention centers, prisons, and other types of residential facilities presents many challenges. Although there is no doubt that adolescents in many high-risk settings are at increased risk for hepatitis B and human papillomavirus, acute medical and psychological problems may consume all of the provider's time and resources. Potential health threats such as vaccinepreventable diseases must necessarily be given lower priority. Lack of vaccination expertise, supplies, and access to records further complicate delivery of vaccines. Since the 1990s, a number of approaches have been used to deliver hepatitis B vaccine to adolescents in many high-risk settings. Close collaboration among state and federal programs, local health departments, and community-based organizations has been necessary to introduce and sustain the delivery of vaccines to these young people. Medicaid, Statute 317 of the Public Health Service Act, the Vaccines for Children program, and State Children's Health Insurance Program have been used to finance vaccinations for adolescents 18 years or younger, and the expanded Medicaid option in the Foster Care Independence Act of 1999 has been used for adolescents older than 18 years of age. A number of states allow adolescents under age 18 to consent to their own hepatitis B vaccination under laws passed to allow treatment of sexually transmitted infections without parental consent. In this article, we present the experiences of several model programs that developed successful hepatitis B vaccination programs in venues that serve adolescents at risk, the important role of state laws and state agencies in funding immunization and other preventive health services for adolescents in high-risk situations, and discuss barriers and means to resolve them. I N THEIR SENTINEL 1993 report, the National Research Council proposed that the focus for addressing high-risk behaviors by adolescents should move from the individual adolescents to the settings in which these adolescents live. 1 These settings include those that serve adolescents who are unauthorized migrants or homeless and those who are in alternative schools, detention centers, jails, and prisons (Table 1). [2][3][4][5][6] The populations served in these settings were formally defined in the McKinney-Vento Act, which was signed into law in 1987. 7 Many of these settings have long been the focus of special efforts to deliver hepatitis B vaccine and serve populations especially likely to benefit from new vaccines for adolescents, including those against human papillomavirus, pertussis, and meningococcal meningitis. This report excludes adolescents who are displaced as a result of natural or man-made disasters, refugees, and foreign students.Health care, including immunization, for the adolescents considered here is generally provided by local, state, and federal programs and their grantees. Unfortunately, missing vaccinations are b...