Patients with ischemic heart disease may have left ventricular (LV) dysfunction due to reversible or irreversible causes. The ability to distinguish viable myocardium with dysfunction due to a reversible etiology (hibernation, stunning) from nonviable scar is critical for determining proper management of the patient. Cardiovascular magnetic resonance (CMR) is a technique that has been established to be useful for the detection of myocardial viability and advancements in the field promise to further increase its utility. In this review we describe the features of CMR that make it suited for this purpose and outline promising developments that may soon make CMR the reference standard for viability assessment.