The assessment of myocardial viability is a crucial step in the work-up of patients with coronary artery disease and left ventricular (LV) systolic dysfunction. Myocardial revascularization should be considered in patients with viable myocardium and LV systolic dysfunction, since this could improve LV function and outcomes.Noninvasive imaging plays a key role in the study of viability and different modalities are currently available, including cardiac magnetic resonance, stress echocardiography and nuclear imaging. The definition of myocardial viability is different, depending on the imaging technique used and it is important for cardiologists to know the information that each modality can offer in this setting.