Imperforate hymen is an obstructive anomaly of the female reproductive tract which occurs in less than 0.1 % of newborns. Not performing an adequate gynecologic physical examination in symptomatic adolescent girls due to embarrassment can often delay its diagnosis. We present the case of an adolescent girl without menarche who was referred to our hospital for cyclic abdominal pain associated with an abdominal mass accompanied by urinary retention and constipation. Examination of her external genitalia allowed rapid diagnosis after a 2-year history of these symptoms.