Premature ovarian "failure" (POF) is an enigmatic and heterogeneous disorder characterized by amenorrhea, hypoestrogenism, and hypergonadotropinism that occurs in women under the age of 40 years. The predominant causes are different in the adolescent, and more of these causes are associated with permanent cessation of ovarian function. It would seem that the more common causes of POF in adolescents include cytogenetic abnormalities involving the X chromosome, ovarian dysfunction occurring in association with other autoimmune endocrine disturbances, and chemotherapy and/or radiation therapy given for any of a number of malignancies. Special challenges in the adolescent beyond establishing the diagnosis include counseling the young woman and her family and discussing the possibility of future pregnancy. Lifelong therapy must be addressed as well. Any discussion of POF raises numerous unanswered questions that should be the focus of future research.