Abstract BACKGROUND: Childhood obesity is associated with many cardio-metabolic risk factors, and different anthropometric measures have been considered to be associated with these risk factors. The aim of this study was to determine the best anthropometric index associated with cardio-metabolic risk factors among obese children and adolescents. METHODS: This study was conducted by using data of the records of 2064 obese children and adolescents aged 6-18 years. Body mass index (BMI), waist circumference (WC), waist- to- hip ratio (WHR) and waist- to-stature ratio (WSR) were considered as anthropometric indexes. The cardio-metabolic risk factors were total cholesterol (TC), LDL-cholesterol (LDL-C),HDL-cholesterol (HDL-C), triglycerides (TG), fasting blood sugar (FBS), diastolic and systolic blood pressure (SBP and DBP).Data were analyzed with SPSS16 using Receiver Operator Curve (ROC) and Pearson correlation analyses. RESULTS: The prevalence of high LDL -C, TC, TG, FBS, SBP / DBP and low HDL - C was higher in boys than in girls. No single anthropometric index was found to be associated with risk factors in different sex and age groups. BMI, WC and WSR but not WHR had significant correlation with TC, LDL - C, TG, and FBS, whereas HDL - C had no significant correlation with anthropometric indexes. CONCLUSION: Our results showed that in spite of all its limitations in differentiating fat mass and obesity pattern, BMI can be considered as a useful anthropometric index for predicting cardio-metabolic risk factors in obese children and adolescents. It may be clinically useful in pediatric population to routinely use WC and WSR -but not WHR- as a screening tool to identify at-risk children. Keywords: Anthropometric measures, fat distribution, cardiovascular risk factors, children.