Premature ovarian failure (POF) is gonadal failure before the age of 40 years. Several rare causes have been discovered yet we still fail to identify the cause in many cases. Although it was once thought to be a permanent condition, a substantial number of patients experience spontaneous remissions and even pregnancy. HRT remains the cornerstone of treatment and the only proven method of achieving pregnancy in these patients is by ovum donation. New alternatives to HRT and fertility preservation are under development. Basic understanding of ovarian physiology and pathogenesis of POF is necessary for the development of newer therapies.