Objective: To determine plasma concentration of tumor necrosis factor alpha (TNF-alpha) in obese and non-obese women with polycystic ovary syndrome (PCOS). Design: Case control study. Participants: Women with diagnosis of PCOS and age-matched healthy controls, the latter with regular periods and normal ovaries according to ultrasound. Interventions: Participants were divided in four groups (group A: PCOS and obese; group B: PCOS and nonobese; group C: obese controls; and group D: non-obese controls) according to body mass index (obese > 30 kg/m2 y and non-obese < 25 kg/m2). Main outcome results: Concentrations of luteinizing hormone, follicle-stimulating hormone, androstenodione, testosterone, sex hormone-binding globulin, serum glucose, insulin and TNF-alpha. Results: Obese and non-obese women with PCOS had higher luteinizing hormone, follicle stimulating hormone, androstenodione. testo...