Deferasirox (ICL670) has been shown to have rapid accessibility to intracellular labile iron. We tested the hypothesis that oral deferasirox improves arterial dysfunction in patients with beta-thalassaemia major. Nineteen thalassaemia patients, aged 23 +/- 7 years, with normal left ventricular (LV) function were treated with deferasirox at 25-35 mg/kg/d for 12 months. LV function, brachial arterial flow-mediated dilation (FMD), carotid arterial stiffness, and serum ferritin levels were determined at baseline prior to initiation, after 6 months and after 12 months of therapy. The baseline cardiovascular indices were compared with those of 17 age-matched controls. Longitudinal changes in patients during the treatment period were also determined. Compared with controls, patients had similar echocardiographic indices of LV function (all P > 0.05), while their baseline brachial FMD was reduced (P < 0.001) and carotid stiffness increased (P = 0.019). An increase in FMD (P < 0.001) and a decrease in carotid stiffness (P = 0.007) were found at 6 and 12 months follow-up. The stiffness index correlated inversely with FMD (r = -0.42, P = 0.001). Although there was an increase in ferritin level at 12 months (3303 +/- 1185 ng/ml vs. 2714 +/- 780 ng/ml at baseline, P = 0.006), no significant correlation existed between ferritin level and FMD or carotid stiffness. In conclusion, deferasirox therapy in thalassaemia patients is associated with improved arterial function.