Weight management is central to the treatment of infertile women with polycystic ovary syndrome. Both body mass index and waist circumference are measures of obesity. The objective of the study was to examine the clinical importance of waist circumference and body mass index in predicting insulin resistance. The cross-sectional study involved a total of 126 consecutive infertile women with polycystic ovary syndrome attending the Infertility unit of the Department of Obstetrics and Gynaecology of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from January 2017 to December 2017. The anthropometric measurements like weight, height and waist circumference were made and body mass index and waist hip ratio were calculated. Fasting insulin and fasting plasma glucose were estimated in early follicular phase of menstrual cycle. Insulin resistance was calculated with HOMA-IR. Body mass index and waist circumference were examined for clinical prediction of insulin resistance by ROC curve analysis. The mean age was 25.56±3.90 years. Mean body mass index was 26.79±3.25, mean waist circumference was 90.9±9.4cm. By body mass index thresholds, 47.9% of the women were overweight, 39.7% of the women were obese. By waist circumference threshold, 80.2% of the women were centrally obese. Body mass index and waist circumference, both had significant correlation with hyperinsuliaemia. When body mass index and waist circumference were examined for predicting insulin resistance by sensitivity, specificity, positive likelihood ratio and negative likelihood ratio, waist circumference appeared to have moderate clinical importance compared to the negligible role of body mass index. Waist circumference may be a better predictor of insulin resistance than body mass index in infertile women with polycystic ovary syndrome.