Introduction: Obesity and hypertension are associated with organ complications, including kidney diseases. It is necessary to search for the methods of early detection of these complications. Aim: The aim of the study was to assess renal function in obese adolescents, based on lipocalin-2 and cystatin C levels in relation to creatinine, estimated glomerular filtration rate and leptin levels. Materials and methods: The study included 76 children aged 11–17 years, with obesity or with obesity and obesityinduced hypertension or normosthenic children with tension headaches (control group). Renal function was assessed based on serum creatinine and estimated glomerular filtration rate (Schwartz equation). Plasma and urine lipocalin-2, serum cystatin C and leptin levels were determined by ELISA. Results: Renal function assessed by creatinine level and estimated glomerular filtration rate was normal in all patients, but mean creatinine levels were significantly higher and estimated glomerular filtration rate was significantly lower in the study groups compared to controls. No significant differences were found in plasma and urine lipocalin-2 levels. Mean cystatin C level was significantly higher in the obese group. We have found a weak positive correlation between plasma lipocalin-2 and creatinine levels and its weak negative correlation with estimated glomerular filtration rate, as well as a positive correlation for leptin and cystatin C levels in the obese group. Conclusion: The role of plasma and urine lipocalin-2 and serum cystatin C in the assessment of renal function in obese adolescents with or without obesity-induced hypertension is ambiguous. The relationship between cystatin C and leptin levels in obese children also requires further research.