Adolescents with malignancy represent a unique population in oncology that traditionally has received care at a variety of institutions. Recent data have shown that clinical trial involvement and patient outcomes in this age group may be influenced by the type of hospital at which they are treated. This article examines factors influencing the location of treatment of patients aged 15 to 19 years from selected areas in Ohio. Patients 15 to 19 years of age with malignancy from the selected 45 counties between 1996 and 1999 were identified from the Ohio Cancer Incidence and Surveillance System database. Factors analyzed included specific diagnosis, age, race, and treating institution. A total of 169 patients were identified, with 46.7% treated at pediatric institutions, 24.8% at adult academic centers, and 28.5% at community hospitals. Diagnosis influenced treatment location: leukemias, central nervous system tumors, and sarcomas were treated more often at pediatric hospitals, whereas melanoma was more often treated at adult academic centers. Patient age and distance from an academic center were also found to affect the location of treatment. Specific diagnosis, age, and geographic location influence the site of treatment of adolescent patients. Efforts to improve survival and increase enrollment in clinical trials must take these factors into account.