A 15-item questionnaire was used to evaluate competency to consent to hospitalization in 30 adolescent psychiatric inpatients. For competency, 17 percent of the subjects met minimal clinical criteria, 30 percent met broad clinical criteria, and 37 percent satisfied legally oriented criteria. Only 22 percent of the adolescent subjects met combined clinical and legal criteria. When compared with previously studied adult voluntary and adult involuntary inpatients, the data more closely resemble those generated by involuntarily admitted adults. Consistently deficient performance on the minimal clinical criteria indicates that adolescents may have a poor understanding of the most general determinants of their hospitalization. Conversely, adolescents performed more favorably than voluntary and involuntary adults on the legally oriented criteria, demonstrating their better cognitive ability to understand such abstract concepts. Thus, specific types of judgment and insight may be essential components in the evaluation of adolescent competency to consent to psychiatric hospitalization.