Cardiomyopathies are primarily the diseases of myocardium associated with cardiac dysfunction. According to the World Health Organization classification, cardiomyopathies can be classified as either primary or secondary. Heritable cardiomyopathies are primary myocardial diseases caused by inherited gene defects. Causes of secondary cardiomyopathies are diverse and include ischemia, infection, toxins, metabolic syndromes, arrhythmias, and congenital malformations associated with pressure or volume overload. Improvement in outcomes and prevention of coronary artery disease has led to the emergence of a new epidemic, the heart failure epidemic. Heart failure affects 4.5 million patients in the United States and is responsible for 300,000 deaths annually. Heritable cardiomyopathies constitute a substantial number of these cases. During the past decade,advances in molecular genetics have provided better insight into the molecular pathophysiology and genetic basis for heritable cardiomyopathies.