Neuromuscular diseases (NMD) are a broadly defined group of disorders that all involve injury or dysfunction of peripheral nerves, neuromuscular junction or muscle, often with dominant or recessive pattern of inheritance. Cardiac involvement is uncommon, in particular with cardiomyopathies and brady/tachyarrhythmias. The causes of cardiac involvement are unclear: replacement fibrosis, alteration of membrane permeability, sympathetic hyperactivity, or accumulation of toxic metabolites can play a role in the pathogenesis of cardiac disorders. The early diagnosis is of pivotal importance to prevent evolution of the disease: electrocardiographic alterations and arrhythmias, particularly if associated with family history for cardiomyopathy or sudden death, can be an early signal of cardiomyopathy associated with NMD. Genetic analysis can improve prognostic stratification, particularly related to arrhythmic risk, and guide to a tailored therapy.