['We evaluated carotid intima-media thickness (CIMT) as an early marker of atherosclerosis, as well as its main determinants among androgen excess, obesity and insulin resistance, in patients with polycystic ovary syndrome (PCOS).', 'We selected 40 PCOS patients and 20 non-hyperandrogenic women who were similar in terms of age and grade of obesity. Complete clinical, metabolic and hormonal profiles and left common CIMT measurements were obtained.', 'Patients with PCOS presented with increased mean CIMT values when compared with controls (F = 8.575; P = 0.005), and this was independent of obesity. Five PCOS patients but no controls had increased CIMT values. CIMT correlated directly with serum total and free testosterone, androstenedione and dehydroepiandrosterone-sulfate levels and mean 24-h heart rate (HR), and inversely with the insulin sensitivity index (ISI), but no correlation was observed with the body mass index (BMI). Multiple stepwise linear regression models showed that in PCOS patients, the main determinants of CIMT were serum total testosterone or androstenedione concentrations, with no influence of ISI or the mean 24-h HR.'] Is androgen excess associated with the increased carotid intima-media thickness observed in young women with polycystic ovary syndrome?