Cardiomyopathies are a clinically and genetically heterogeneous group of cardiac diseases in which the myocardium is primarily involved. Mitochondrial DNA point mutations have been identified in a broad spectrum of mitochondrial disorders, which are associated with neurological diseases. However, they also have been reported in patients with cardiomyopathy, either alone or as part of a multisystem disorder. A patient who presented with severe heart failure and was diagnosed as having a mitochondrial A3243G mutation is described.