Cardiomyopathies are a major cause of morbidity and mortality worldwide, and currently are the most common group of disorders leading to cardiac transplantation. Recent advances in the field of molecular medicine have provided significant molecular genetic insight into a variety of both primary and secondary cardiomyopathies. The purpose of this review is to briefly describe the known primary and secondary causes of cardiomyopathy; describe the molecular genetic abnormalities associated with them, if known; and describe the current progress being made within this area of molecular cardiology.