Polycystic ovary syndrome (PCOS) is a mainly hyperandrogenic disorder and is possibly the most frequent endocrinopathy in premenopausal women. Androgen excess is the primary defect in PCOS, because ovarian theca cells secrete increased amounts of androgens even after several passes in primary culture. Excessive androgen amounts might favor the visceral deposition of body fat in affected women, resulting in insulin resistance, compensatory hyperinsulinism and further androgen excess. This vicious circle starts early during life in women with PCOS, even during fetal development, manifests clinically during puberty and does not end after menopause. All the steps in the vicious circle contribute to the association of PCOS with metabolic dysfunction and cardiovascular risk factors. Fortunately, most, if not all, of the therapeutic strategies currently in use for the management of PCOS, including lifestyle modification and diet, oral contraceptives, antiandrogens and insulin sensitizers, may ameliorate androgen excess and its long-term consequences.