The polycystic ovary syndrome (PCOS) often presents in adolescence with menstrual disorders, acne and hirsutism. The early diagnostic signs are sometimes dismissed as 'normal' changes of adolescence, and the opportunity to save the teenager from the stigmata of the syndrome is missed. The finding that the metabolic syndrome is a possible long-term sequela of PCOS now presents a challenge to make an early diagnosis, educate patients regarding the importance of weight control and exercise, and treat accordingly both symptomatically and prophylactically. The use of long-term insulin sensitizers, particularly metformin, for these purposes in adolescents is now the subject of an inter-disciplinary debate. Good, hard supportive data are not yet forthcoming but, as in the adult, the establishment of metformin treatment for the hyperinsulinaemic adolescent with PCOS may precede the evidence.