The objective of this chapter is to introduce the cardiomyopathies. Cardiomyopathies (CMPs) are heart muscle disease of unknown causes. It affects the structural and functional ability of myocardium. Cardiomyopathy is a unique condition associated with cardiac dysfunction. CMPs are diagnosed different from coronary artery disease, hypertension, valvular disease or pericardial disease. This chapter covers the classification, incidence and etiology, pathophysiology, clinical manifestations, diagnositc evaluation, and management. Cardiomyopathies are basically classified as primary or secondary. Primary CMPs are with unknown etiology. The secondary CMPs are caused due to myocardial diseases such as ischemia, viral infections, alcohol intake, drug abuse and pregnancy.