Polycystic ovary syndrome ( PCOS ) is the most important cause of an anovulation, hirsutism and infertility in women. It is a heterogeneous syndrome the etiology of which is not known clearly yet. This multifactorial syndrome starts at puberty and its cardiovascular and metabolic sequelas are observed during menopause. Adolescent patients pose particular diagnostic problems as characteristics of normal puberty often overlap with signs and symptoms of PCOS. However, identification of PCOS during adolescent period is important in order to prevent long term sequelas. It is beneficial to set a behavior pattern in this age group with regard to appropriate diet and exercise. On the other hand, whether to treat PCOS in adolescents in order to prevent long term sequelas is still controversial.