Shifts in the use of mental health services by adolescents between 1975 and 1986 are examined by levels of care--outpatient, partial hospitalization, residential treatment center, and inpatient. Data from National Institute of Mental Health surveys of U.S. facilities include client characteristics (age, sex, race, diagnosis, clinical history) and treatment characteristics (referral source, type of intervention, length of stay). Major increases in mental health service use were observed for all levels of care during this period. Nonetheless, a relatively small percent (less than 2%) of adolescents in the U.S. received any type of mental health service in 1986. The clinical and treatment variables available were only moderately helpful in differentiating levels of care.