OBJECTIVES: Iron chelators (deferasirox or desferrioxamine) are essential to patients who need life-long blood transfusion (e.g. β-Thalassemia). However, in 2010, the US Food and Drug Administration (FDA) had issued a warning on potential adverse events associated with iron chelators, especially deferasirox. The objective of this retrospective cohort study was to compare the risk of renal impairment, hepatic impairment, and gastrointestinal bleeding in patients with transfusion-dependent anemia using deferasirox or desferrioxamine. METHODS: Patients with transfusion-dependent anemia (sickle cell disease, β-thalassaemia, myelodysplastic syndrome and aplastic anemia) and were prescribed iron chelators (deferasirox or desferrioxamine) were identified from the 2005 -2009 Taiwan's National Health Insurance database. Cox proportional hazards models were used to assess the association between iron chelators and occurrences of adverse events (renal impairment, hepatic impairment, and gastrointestinal bleeding). All models adjusted for age, sex, drug exposure (days), type of transfusion-dependent anemia and medical history. RESULTS: Patients were categorized into deferasirox (n=180), desferrioxamine (n=586) ,and mixed users (n=202), based on the drug they received during the follow-up. The crude rates of adverse events were 4.14, 3.16 and 0.65 per 10,000 person-year in deferasirox, desferrioxamine and mix users, respectively. After adjusting covariates, there was no association between deferasirox and adverse events (hazard ratio [HR]0.84; 95% CI, 0.59–2.00) compared to desferrioxamine users. CONCLUSIONS: In this population-based analysis, transfusion-dependant anemia patients using deferasirox and desferrioxamine were at similar risk of adverse events.