Obesity and insulin resistance is a common finding in patients with polycystic ovary syndrome (PCOS). Significant number of PCOS women experience insulin resistance that is irrespective of the degree of obesity suggesting possible genetic basis. Therefore, several polymorphisms of the genes encoding for the insulin (INS), insulin receptor (INSR) or insulin receptor substrates (IRS) involved in postreceptor signaling have been explored for their association with abnormal sensitivity to insulin in PCOS. The aim of the present study was to determine whether selected polymorphisms of INS, INSR and IRS-1 are associated with the development of PCOS as well as with increased insulin resistance in Croatian women with PCOS. The study enrolled 150 women with PCOS and 175 control women. The diagnosis of PCOS was based on Rotterdam consensus criteria. Each subject underwent an evaluation of body mass index (BMI), hirsutism, acne and menstrual cycle abnormalities as well as follicular stimulating hormone (FSH), luteinizing hormone (LH), total and free testosterone, androstendione, dehydroepiandrosterone sulphate (DHEAS), sex hormone binding globulin (SHBG), fasting glucose and fasting insulin. Insulin resistance (IR) was quantified using the homeostatic model assessment of IR (HOMA-IR). Molecular analyses for the genetic polymorphisms were preformed. There was a significant difference in clinical and biochemical characteristics of the studied groups except for BMI and fasting glucose levels. No significant differences were observed in the genotype and allele distribution of the VNTR INS, C/T INSR, Gly792Arg IRS-1 polymorphisms between cases and controls. Moreover, no association was found between VNTR INS, C/T INSR and Gly792Arg IRS-1 polymorphism and parameters of insulin resistance in PCOS patients. In conclusion, our data does not support an association between VNTR INS, C/T INSR and Gly792Arg IRS-1 polymorphism and susceptibility to PCOS or insulin resistance in Croatian women with PCOS.