BACKGROUND: Low-grade inflammation, indicated by elevated serum high-sensitivity CRP (hS-CRP), is commonly observed in children and adolescents with overweight or obesity. This study evaluated serum hS-CRP in relation to body fat parameters, lifestyle characteristics, and potential biological determinants (leptin, HDL cholesterol, and 25-OH vitamin D) in a Belgian population. METHODS: Anthropometric measurements, biochemical results, and lifestyle questionnaires were analyzed from 267 children and adolescents with overweight or obesity. RESULTS: Median (P10, P90) serum hS-CRP concentration was 1.8 mg/L (0.5, 5.4). In total, 73 subjects had an elevated hS-CRP (≥ 3 mg/L). Children with elevated hS-CRP, irrespective of sex and pubertal status, had higher total body fat mass (BIA) ( CONCLUSIONS: A quarter of Belgian children with overweight/obesity have elevated hs-CRP concentrations. This study supports the use of WHtR in clinical practice for the evaluation of children with overweight/obesity, given its association with low-grade inflammation.