An observational study was conducted to explore postmarketing safety and efficacy of Deferasirox (DFX) in comparison with conventional Desferrioxamine (DFO) in chelation-naïve children with transfusional iron overload. Transfusion-dependent children (aged ≤ 5 yr) who had serum ferritin above 1000 μg/L and had been prescribed either first-line DFX or DFO for at least 12 months to maintain serum ferritin between 500 and 1000 μg/L were included. Initial DFX dose was 20 mg/kg/d for 7 d a week, and DFO dose was 25-35 mg/kg/d subcutaneously, given for 5 d a week. Dose adjustments were based on serum ferritin changes and safety markers. The primary efficacy endpoint was change in serum ferritin from baseline. The effect of transfusional iron loading rate (ILR) and different doses of chelators on serum ferritin was also assessed. A total of 111 patients were observed for a median of 2.29 yr on DFX (n = 71) and 2.75 yr on DFO (n = 40). Absolute change in serum ferritin from baseline to the last available observation was not significant with DFX (91 μg/L, P = 0.5) but significantly higher with DFO (385 μg/L, P < 0.005). ILR and DFX doses had a major impact on serum ferritin changes in DFX cohort. The height- and weight-standard deviation scores did not differ significantly in both cohorts during the study. Fluctuations in liver enzymes and non-progressive increase in serum creatinine were the most common adverse events (DFX; 9.8%, 18.0% and DFO; 5.0%, 7.5%, respectively). DFX is well tolerable and at least as effective as DFO to maintain safe serum ferritin levels and normal growth progression in chelation-naïve children. © 2012 John Wiley & Sons A/S.