Polycystic ovarian syndrome is the most common form of anovulatory infertility.1 Its association with menstrual disturbance and altered hormonal parameters leads many affected women of reproductive age to attend a gynaecology or infertility clinic. The aetiology of the condition is unknown, but recent evidence suggests that the principal underlying disorder is one of insulin resistance, with the resultant hyperinsulinaemia stimulating excess ovarian androgen production. Associated with the prevalent insulin resistance, these women exhibit a characteristic dyslipidaemia and a predisposition to non-insulin dependent diabetes and cardiovascular disease in later life. Thus, polycystic ovarian syndrome seems to have many of the hallmarks of the metabolic syndrome.2^–4 This article focuses on the recent change in attitudes to polycystic ovarian syndrome arising from the link with insulin resistance—a concept that not only has major implications for the health of affected women but also offers a potential for new treatments.