Life span, causes of death, weight of heart, liver, brain, and main pathological changes of internal organs were analysed on 329 autopsy cases of muscular dystrophies. These included 249 cases of Duchenne muscular dystrophy (DMD), 3 Becker muscular dystrophies (BMD), 14 limb-girdle muscular dystrophies (LGMD), 3 fascioscapulohumeral muscular dystrophies (FSH), 18 Fukuyama type congenital muscular dystrophies (FCMD) and 17 myotonic dystrophies (MyD). In DMD the life span has definitely prolonged in recent years. Pulmonary infection, which was once the major cause of death, has greatly decreased in recent years. Instead, respiratory and cardiac failures caused by dystrophic changes of respiratory and cardiac muscles were more closely related to the causes of death in many recent cases. Myocardial fibrosis was observed in most of the patients with DMD, BMD, LGMD, FCMD and MyD. The distribution of cardiac lesions was similar in BMD, LGMD and FCMD as in DMD. In MyD the disorders involved more frequently conductive muscles resulting in arrhythmias. The dystrophic cardiomyopathy seemed to be a part of the essential changes in all types of muscular dystrophy, although different in intensity and rate of morbidity. Alzheimer's neurofibrillary changes were observed in the brain of some cases of FCMD and MyD, suggesting the possibility of precocious aging of the brain in some patients of the muscular dystrophies.