AIM: Irisin, a newly discovered adipomyokine, has pleiotropic effects in metabolic and energy homeostasis, insulin resistance (IR), and browning of white adipose tissue. The aim of this study was to evaluate irisin levels in children with obesity and also to elucidate possible relationships between irisin with anthropometric obesity indices, parameters of metabolic syndrome (MetS), and intima media thickness (IMT). METHODS: A total of 77 prepubertal children, 4-12 years old, were enrolled in this study, including 44 children with obesity (BMI ≥ 95th percentile) and 33 normal weight controls of matched age and gender. Detailed clinical examination, anthropometric parameters, laboratory data, including serum irisin levels, using ELISA technique and cIMT measurement were carried out in all subjects. RESULTS: Children with obesity had significantly higher values of irisin compared to controls (p = 0.003) independently of age, gender, or IR status. Irisin levels were positively correlated with weight z-score, Body Mass Index (BMI), BMI z-score, % Body Fat, waist circumference (WC), triglycerides (TG), and HOMA-IR (p = 0.016, p = 0.025, p = 0.028, p = 0.035, p = 0.019, p = 0.049, p = 0.007 respectively) and inversely correlated with HDL (p = 0.037). In multiple regression analysis irisin levels were strongly associated with excess adiposity (p <
0.001) and uric acid (p = 0.054). CONCLUSION: Children with obesity showed an unfavorable cardiometabolic profile and higher levels of IMT and irisin. Moreover, irisin was correlated with metabolic parameters, suggesting that irisin can serve as a prognostic index for future development of MetS in children with obesity.