Polycystic ovary syndrome (PCOS) is the commonest cause of anovulatory infertility, menstrual disturbances and hirsutism. PCOS is also associated with a metabolic disturbance characterised by hyperinsulinaemia and insulin resistance. Women with PCOS are at increased long-term risk of developing type 2 diabetes (T2DM) and carry a significant risk factor profile for cardiovascular disease. Obesity amplifies both reproductive and metabolic dysfunction. A growing body of evidence also highlights the high prevalence of anxiety and depression amongst women with the syndrome. The diagnosis of PCOS is made principally on clinical grounds, supported by a small number of biochemical investigations. The choice of investigations in women with PCOS depends primarily on the mode of presentation. Treatment should be tailored to the presenting complaint. For example, in infertile women, induction of ovulation can be achieved in most cases by the use of antioestrogens. Weight reduction in obese subjects with PCOS not only increases the chance of fertility but will also improve the long-term prognosis with regard to development of diabetes. Symptoms of androgen excess (hirsutism, persistent acne) are best managed by suppression of ovarian androgens, using a combined oral contraceptive, supplemented, if necessary, by androgen receptor blockade. Insulin sensitizing drugs such as metformin have a place in regulation of menses and in reducing risk of T2DM. Psychological support may be needed for those with anxiety and depression.