Abstract To assess the prevalence and severity of premenstrual symptoms in adolescents, we administered the Premenstrual Assessment Form, a 95-item instrument previously validated in adults. Adolescent females ( n = 207) at a suburban-based adolescent health service completed the form. Subjects had a mean age of 17.6 years, 89% were white, 59% were in high school, 28% were in college. Almost all subjects reported at least one premenstrual change of minimal (96%) or moderate (89%) severity, while many reported changes they considered severe (59%) or extreme (43%). The most commonly reported changes in physical condition were general discomfort and water retention symptoms, fatigue, and autonomic physical changes. The most commonly reported changes in mood and behavior included impaired social function, depressive changes, and impulsive behavior. These changes matched almost exactly those previously reported in adults and were most severe in those adolescents who reported having dysmenorrhea and were not on an oral contraceptive. We believe that clinicians and researchers who evaluate and treat adolescents should view the physical and emotional complaints of teenagers in the context of our findings.