Myocardial siderosis in β-thalassemia major (β-TM) remains the leading cause of death. Deferasirox (DFX), a new iron chelation treatment, has proved to be effective in reducing or preventing cardiac iron burden in thalassemic patients according to clinical trials with maximum duration of up to 3 years except one that was recently published and lasted 5 years. The aim of this study was to evaluate the efficacy of DFX in reducing or preventing cardiac iron burden in 23 patients with β-TM after 5 years of therapy. All patients had a magnetic resonance imaging (MRI) T2* evaluation of their cardiac iron load before starting DFX therapy and after a period of 5 years. Ferritin levels and left ventricular ejection fraction (LVEF) were also evaluated at the same time. Deferasirox was administered in a starting dose of 30 mg/kg/day and never increased to more than 40 mg/kg/day. The MRI T2* cardiac iron load mean values before DFX was 32.82 ± 10.86 ms, and after 32.13 ± 7.74 ms, showing a stability in MRI T2* myocardial value but a significant improvement in two patients with an intermediate iron load (12 vs. 23 ms). The mean LVEF value was 68.43 ± 7.08% before treatment with DFX and 67.95 ± 5.94% after DFX therapy without significant change. Our results confirm previous studies that DFX is considered an effective chelating agent used as monotherapy for at least 5 years and is more efficacious in moderate to severe cardiac iron loaded thalassemic patients.