Abstract OBJECTIVE: To define the prevalence and the features of polycystic ovary syndrome (PCOS) in patients with psoriasis. To our knowledge, the association between PCOS and psoriasis has not been explored in previous studies. Psoriasis is linked with metabolic syndrome, insulin resistance, and non-alcoholic fatty liver disease, which are features often associated with PCOS. DESIGN: A cross-sectional analysis was performed between January 2010 and April 2012. SETTING: Unit of human reproductive pathophysiology, Catholic University Hospital. PATIENT(S): We prospectively analyzed 51 patients with psoriasis and 102 healthy age- and body mass index (BMI)-matched controls. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): The prevalence and characteristics of PCOS women of reproductive age with chronic plaque psoriasis. RESULT(S): The prevalence of PCOS was greater in patients with psoriasis than in matched control subjects (47.05% and 11.76%, respectively; odds ratio, 6.66; 95% confidence interval 2.95-15.07). Among the women with psoriasis, the prevalence of Psoriasis Area and Severity Index ≥10 was higher in patients with PCOS than in subjects without PCOS (odds ratio, 3.5; 95% confidence interval 1.04-11.72). CONCLUSION(S): The prevalence of PCOS in women with psoriasis is remarkably greater than in age- and BMI-matched control women.