To investigate the relationship between 8 endocrine-disrupting chemicals in the serum and insulin resistance in patients with polycystic ovary syndrome (PCOS).This study was conducted among 60 patients with PCOS, including 23 with insulin resistance (PCOS-IR) and 37 without insulin resistance (PCOS-NIR), and 29 non-PCOS women seeking medical attention for infertility or menstrual disorder (control group). The serum levels of 6 phthalic acid esters (PEAs), bisphenol A (BPA) and octylphenol (OP) were measured in all the subjects.The levels of PAEs, BPA and OP showed no significant differences between PCOS patients and the control group (P0.05). The serum level of OP was significantly lower in patients PCOS-IR than in those with PCOS-NIR (47.89 ng/ml vs 60.24 ng/ml, P0.05).PEAs and BPA do not produce obvious effect on the pathogenesis of PCOS or contribute to insulin resistance, but OP may play a role in insulin resistance in PCOS patients.