AbstractThe cardiac function of 36 males with Duchenne muscular dystrophy was evaluated by echocardiography, and the results were compared with the results of other tests of cardiac involvement, including serum creatine kinase isoenzyme evaluation, electrocardiography, chest x‐ray, and physical examination of the heart and lungs. Although correlation between the various methods of assessment was not impressive, the echocardiographic technique appeared to be useful in evaluating and following the cardiomyopathy in these patients. Several aspects of left ventricular function were abnormal in most patients, and only two of the 36 had normal left ventricular size and function. Electrocardiographic abnormalities were also apparent in all patients, although the changes were mild in four of the 36. Clinical evalution, isoenzyme determinations, and chest x‐rays have not been useful in assessing cardiac function. The echocardiographic data on these 36 patients are presented in detail and the patients will now be followed sequentially to attempt evaluation of ongoing changes.