Serological testing of adolescents to determine the presence of antibodies to HIV raises significant medical, ethical, legal, psychological, social, and political issues. The limited availability of effective medical interventions for asymptomatic HIV infection suggests that a cautious approach to testing adolescents be adopted. Risks for adolescents who are tested and found to be seropositive include the possibility of social ostracism and rejection by their families and peers, along with discrimination in education, employment, housing, residential placement, or insurance eligibility. Benefits of testing include the opportunity for adolescents to receive certain treatments or to participate in clinical trials and the use of testing as an impetus for shaping healthy sexual behavior. General principles for testing focus on risks versus benefits of testing, mandatory and routine testing, and confidentiality of test results. Recommendations on HIV testing of individual adolescents encompass voluntary testing, routine testing, mandatory screening, counseling and support, consent for individual testing, anonymous testing sites, and confidentiality. Recommendations on seroprevalence studies and research concern consent for participation and support.