Premature ovarian failure (POF), sometimes termed premature menopause, is an enigmatic disorder. Among the various causes of POF that now have been identified, it is clear that some are present only in those who have no oocytes remaining, whereas others may be associated with remaining follicles and offer the potential for ovulation and spontaneous pregnancy. The causes of POF include cytogenetic abnormalities of the X chromosome, enzymatic defects, defective gonadotropin secretion or action, environmental insults, and autoimmune disorders. The objectives of the evaluation of young women with hypergonadotropic amenorrhea are to identify any treatable causes and any potentially dangerous associated disorders. It is important to make the diagnosis in a timely fashion. In vitro fertilization with donor oocytes is the most effective way of providing a pregnancy for any affected woman, but should be used with caution in women with Turner syndrome and the fragile X premutation.