Objective: Women with polycystic ovary syndrome (PCOS) are at an increased risk for insulin resistance and hyperlipidemia. Metabolic syndrome is a cluster of risk factors that confers an increased risk for cardiovascular disease. The objectives of this study were to compare the prevalence of metabolic syndrome in women with PCOS and controls and to identify the role of androgens or insulin resistance in the development of metabolic syndrome. Methods: Women with PCOS (n = 129) and women with regular menses and no hirsutism seen for an annual examination (n = 177) were studied. Results: The age-adjusted prevalence of metabolic syndrome was higher in women with PCOS (47.3% , 95% confidence interval 35.3-56.9% ) compared with controls (4.3% , 95% confidence interval 1.9-7.6% , P < .001). Compared by age group, the risk of metabolic syndrome in women with PCOS was higher for all groups (P < .001). There were no significant differences in serum androgen levels between women with PCOS with or without metabolic syndrome. In contrast, all markers of insulin resistance were abnormal in women with PCOS with metabolic syndrome compared with those without metabolic syndrome (P <.001). We found serum triglyceride/high density lipoprotein cholesterol (TG/HDL-C) ratio correlated with insulin resistance in this population (P <.001). Serum TG/HDL-C >3.2 has a high sensitivity and specificity for the detection of metabolic syndrome in women with PCOS. Conclusion: Women with PCOS have a 11-fold increase in the prevalence of metabolic syndrome compared with age-matched controls. The risk of metabolic syndrome is high even at a young age, highlighting the importance of early and regular screening. The TG/HDL-C ratio may serve as a screening tool and needs to be prospectively validated in this group. Objective: Women with polycystic ovary syndrome (PCOS) are at an increased risk for insulin resistance and hyperlipidemia. The objectives of this study were to compare the prevalence of metabolic syndrome in women with PCOS and controls and to identify the role of androgens or insulin resistance in the development of metabolic syndrome. Methods: Women with PCOS (n = 129) and women with regular menses and no hirsutism seen for an annual examination (n = 177) were studied. Results: The age-adjusted prevalence of metabolic syndrome was higher in women with PCOS (47.3%, 95% confidence interval 35.3-56.9%) compared with controls (4.3%, 95% confidence interval 1.9-7.6% P <.001). Compared by age group, the risk of metabolic syndrome in women with PCOS was higher for all groups (P <.001). There were no significant differences in serum androgen levels between women with PCOS with or In contrast, all markers of insulin resistance were abnormal in women with PCOS with metabolic syndrome compared with those without metabolic syndrome (P <.001). We found serum triglyceride / high density lipoprotein cholesterol (TG / HDL-C) ratio correlated with insulin resistance in this population (P <.001). Serum TG / HDL-C> 3.2 has a high sensitivity and specificity for the detection of metabolic syndrome in women with PCOS. Conclusion: Women with PCOS have a 11-fold The risk of metabolic syndrome is high even at a young age, highlighting the importance of early and regular screening. The TG / HDL-C ratio may serve as a screening tool and needs to be prospectively validated in this group.