Introduction: Obesity in adolescents can cause metabolic syndrome. Insulin resistance increases the risk of metabolic syndrome, which then increases the risk of premature death. Studies about anthropometric measurements and adiponectin levels as early markers of insulin resistance in obese adolescents are still limited. Methods: A cross-sectional study was performed on 59 obese adolescents aged 13–16 years. Obesity was established on the basis of the Centers for Disease Control and Prevention (CDC) curve (2000). Insulin and blood glucose level measurements were carried out using an enzymatic kit. Adiponectin levels were assayed using enzyme-linked immunosorbent assay (ELISA). The relationships between variables were evaluated by correlation analysis using SPSS. Results: Statistical tests showed a positive correlation between waist circumference (r=0.421; p=0.001) and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) (r=0.396; p=0.002). Waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) had a weak positive correlation with insulin (r=0.343; p=0.008 and r=0.311; p=0.017) and HOMA-IR (r=0.306; p=0.018). There was a weak negative correlation between adiponectin and insulin in obese adolescents (r=-0.278; p=0.033). Conclusion: Anthropometric measurements (waist circumference, WHR and WHtR) and adiponectin can be used for early detection of insulin resistance and hyperinsulinemia in obese adolescents.