Myocarditis is a condition that can have a very wide clinical spectrum ranging from asymptomatic forms to fatal disease, but mostly presenting as new onset heart failure with reduced left ventricular ejection fraction, with or without viral syndrome. This condition is an important cause of sudden cardiac death in young patients. High risk features include second and third degree atrioventricular block or malignant arrhythmias. The diagnostic work-up may be challenging, but non-invasive imaging, primarily cardiac magnetic resonance, plays an increasingly important role, although endomyocardial biopsy is still considered a gold standard for diagnosis. Most importantly, myocarditis can transition to non-ischemic cardiomyopathy with eventually poor outcome. In this review, we will summarize the data on different diagnostic and treatment modalities of this disease.