The management of cardiac involvement is central for Becker muscular dystrophy (BMD) patients since heart failure represents the most frequent cause of death in this population. We performed a comprehensive CMR evaluation of functional and structural myocardial alterations encountered in a cohort of 88 BMD patients. A total of 26% of the BMD patients had a reduced ejection fraction (EF). Globally, native T1, T2 and ECV values were significantly higher in BMD patients than in healthy volunteers, even in sub-clinical phenotypes and correlated with EF. Our results encourage a more systematic inclusion of CMR in the standard of care applied to BMD patients.