BACKGROUND‐Cardiac involvement is a common and well‐recognized feature of many neuromuscular diseases. The types of involvement vary; some are severe and may lead to death, whereas others are mild and often subclinical. Cardiac dysfunction generally manifests during the course of an underlying neuromuscular disease and increases in severity with a longer duration of disease. Cardiac symptoms rarely present as initial manifestations of neuromuscular disease.REVIEW SUMMARY‐Cardiac dysfunction in neuromuscular diseases generally presents with any or all of three cardinal features: heart failure, cardiac arrhythmias, and/or conduction disorder. Dystrophinopathies and Friedreich's ataxia commonly present with cardiomyopathy, whereas myotonic muscular dystrophy and Kearns‐Sayre syndrome present with heart block and a variety of arrhythmias. New diagnostic cardiac technologies and recent molecular, genetic, and biochemical advances have not only helped in accurate diagnosis but have made significant contributions to under‐standing the pathophysiology and prognosis of many cardiomyopathies. In many cases, it is now possible to predict the severity of heart disease directly by DNA analysis.CONCLUSION‐Cardiac manifestations of neuromuscular disease are heterogeneous. There is a high incidence of heart disease in many neuromuscular diseases, but the majority of patients are asymptomatic or mildly symptomatic during the early stages. Early diagnosis of cardiac dysfunction and appropriate treatment may prolong survival and improve quality of life in these patients. It is important to remember that an unexplained cardiac dysfunction could indicate the existence of an underlying neuromuscular disorder.(THE NEUROLOGIST 6:67‐82, 2000)