This study aimed to determine the feasibility, reproducibility, and reliability of the multiecho T*2 Magnetic resonance imaging technique at 3 T for myocardial and liver iron burden quantification and the relationship between T*2 values at 3 and 1.5 T. Thirty-eight transfusion-dependent patients and 20 healthy subjects were studied. Cardiac segmental and global T*2 values were calculated after developing a correction map to compensate the artifactual T*2 variations. The hepatic T*2 value was determined over a region of interest. The intraoperator and interoperator reproducibility for T*2 measurements at 3 T was good. A linear relationship was found between patients' R (1000/T*2) values at 3 and 1.5 T. Segmental correction factors were significantly higher at 3 T. A conversion formula returning T*2 values at 1.5 T from values at 3 T was proposed. A good diagnostic reliability for T*2 assessment at 3 T was demonstrated. Lower limits of normal for 3 T T*2 values were 23.3 ms, 21.1 ms, and 11.7 ms, for the global heart, mid-ventricular septum, and liver, respectively. In conclusion, T*2 quantification of iron burden in the mid-ventricular septum, global heart, and no heavy–moderate livers resulted to be feasible, reproducible, and reliable at 3 T. Segmental heart T*2 analysis at 3 T may be challenging due to significantly higher susceptibility artifacts. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.