To date, little data has been collected from homeless adolescents regarding their access to, and utilization of, health care. In this study, 68 adolescents aged 16-25 were interviewed after being randomly selected from among those who came to a drop-in center for homeless youth in New York City in July 1996. The interviews followed a standardized questionnaire designed to collect demographic information as well as to assess past and current use of medical services. Prior to homelessness, 68% of subjects had been utilizing medical services on a regular basis, and the principal sources of care were as follows: hospital clinics, 51%; community health centers, 33%; and private physician offices, 22% (with more than one facility utilized in some cases). By contrast, 90% of participants reported having received care during homelessness, 68% of whom obtained regular health care at shelters, 32% at drop-in centers, and 25% at hospital clinics. Despite the fact that 42.4% of the sample was covered by health insurance at the time of interview, only 10% of subjects reported having ever been denied health care at any facility visited. Taken together, these findings suggest that, in the population studied, an increase in the percentage of adolescents regularly utilizing medical services occurs upon homelessness, coincident with a shift in utilization from hospital clinics and community health centers to shelters and drop-in centers. These results clearly warrant further study on the access and utilization of health care by homeless adolescents. If substantiated, the present findings call fo renewed efforts toward optimizing health care delivery to homeless adolescents at shelters, drop-in-centers, and other such facilities where these individuals utilize medical resources most frequently.