This is a report of 6 cases of esophageal diverticulum at the mid-thoracic esophagus treated surgically at the Department of Thoracic and Cardiovascular Surgery, Hanyang University Hospital during the 10 years. Five patients were female and one was male and the age distribution was between 31 and 61 years, Various subjective symptoms were noticed preoperatively. Diagnosis was confirmed by esophagography. The type of esophageal diverticulum were pulsion type in five cases and traction type in one case. After diverticulectomy, subjective symptoms disappeared and there were no operative complications and mortality. Recurrence of symptoms was not noticed during follow-up. [KTCS 1983;3:391-398]