Six cases of idiopathic muscular hypertrophy of the esophagus were found at autopsy in a relatively short period of time. As has been the experience in previously reported cases, our finding was incidental at the autopsy in all of the cases. In only one of our patients were there relevant symptoms and radiographic changes that could be attributed to the disease. How often patients with muscular hypertrophy of the esophagus have the clinical syndrome of diffuse esophageal spasm remains unclear. It is therefore evident that only by awareness of this entity can studies of esophageal funtion, x-ray films, and appropriate treatment prevent serious morbidity and occasional mortality from the disease.