Abstract Purpose This study aimed to evaluate iron levels in cardiac and hepatic tissues using magnetic resonance imaging (MRI) T2⁎. Methods Cardiac and hepatic MRI was performed for 93 patients with β-thalassemia major. Results Cardiac T2⁎ was in the range of 2.9–56.6 ms. Myocardial siderosis was detected in 44% of patients; 25 patients had moderate and severe siderosis with serum ferritin level (SFL) of 576–10,284 ng/ml. There was a significant correlation between SFL and cardiac T2⁎ (p<.001). Conclusions The effective role of MRI as a noninvasive producible method in measurement of iron concentration in tissues is not accessible with conventional techniques.