Dilated cardiomyopathy (DCM) is characterized by dilation of the left ventricle combined with a systolic dysfunction without significant coronary artery disease (CAD). DCM is typically not due to a single disease but is the heart’s response to a wide range of diseases and insults including viral illness, genetic cardiomyopathies, and toxins. Cardiac MRI (CMR) can differentiate multiple different etiologies for DCM based on the pattern of hyperenhancement seen by delayed-enhancement MRI (DE-MRI). In the majority of patients with non-ischemic DCM, there is no scar or fibrosis seen by CMR. However, in ~25% of non-ischemic DCM patients, some scar is seen in a non-ischemic pattern. The pathogenesis of scarring is unknown, but with some etiologies, it has been attributed to inflammation or myocarditis. This chapter will focus first on the CMR evaluation of DCM in a patient presenting with heart failure and explore how the use of DE-MRI can differentiate different etiologies of heart failure. The second half will focus on acute myocarditis and the associated CMR findings characteristic of acute myocarditis. Myocarditis is an inflammatory disease of the myocardium. By pathology, myocarditis is diagnosed by the presence of inflammatory infiltrates with adjacent myocyte injury. The presentation of myocarditis varies widely ranging from no symptoms to fatigue and chest pain to sudden cardiac death. By CMR, acute myocarditis is characterized by the presence of epicardial and mid-wall hyperenhancement on DE-MRI, as well as regions of elevated native T1 and T2.