BACKGROUND: Children and adolescents with obesity can now be classified according to metabolic profile, as those with metabolically healthy obesity (MHO) and those with metabolically unhealthy obesity (MUO). We aimed to determine the prevalence of MUO and identify its biochemical predictors in pediatric patients with obesity. METHODS: We evaluated the medical records of 187 boys and girls with obesity. The children were divided into MHO and MUO groups, and anthropometric and biochemical parameters were assessed. Oral glucose tolerance test (OGTT) was used to identify impaired glucose regulation and hyperinsulinism, and binary logistic regression analysis was used to determine predictors of MUO in children with obesity. RESULTS: Of the 187 children, MUO was found in 71.7% (n=134) and MHO in 28.3% (n=53); those in the MHO group were younger than those in the MUO group. Blood pressure, triglyceride, total cholesterol, and uric acid levels were significantly higher in the MUO group than in the MHO group. Further, the MUO group exhibited a significantly higher level of insulin resistance (p<0.05) than the MHO group. Serum levels of uric acid and homeostasis model assessment of insulin resistance index (HOMA-IR) were confirmed as biochemical predictors of the MUO phenotype in children with obesity. CONCLUSIONS: The ratio of MUO in children with obesity was relatively high; further, serum levels of uric acid and HOMA-IR can be used as biochemical predictors of MUO.