Objective To investigate the occurrence of insulin resistance in Chinese women with polycystic ovary syndrome(PCOS),and the relationship between insulin resistance and metabolic syndrome(MetS).MethodsTotal of 578 PCOS patients were included in this study.Data were collected to analyze the prevalence of insulin resistance and the risk for metabolic syndrome.ResultsThe prevalence of Homeostasis model assessment of(HOMA-IR)75th,fasting insulin(FIN)95th,2h-insulin(2h-INS)150 U/L,raised both FIN and 2h-INS,and hyperinsulinemia(HIN,raised FIN and/or 2h-INS)were 57.4%,23.0%,12.6%,8.5% and 27.2%,respectively in these PCOS patients.There were 40.6% patients with raised FIN suffered from MetS;41.1%with raised 2h-INS;39.5% with hyperinsulinemia(HIN,raised FIN and/or 2h-INS);26.8% with raised HOMA-IR.Compared to the patients with normal HOMA-IR,FIN or 2h-FIN,the risk for suffering from MetS was higher(P0.001).ConclusionsThe prevalence of insulin resistance varied from different criteria.Patients met any criteria for insulin resistance had a greater risk of developing of metabolic syndrome.It is worthy to find out and treat the insulin resistance in PCOS patients.