We evaluated diagnostic X-ray and endoscopic examination findings in 486 patients with esophageal achalasia. Concerning the association between the duration of disease and the X-ray dilatation type, the duration was 1-4 years in more than 50% of patients with the Sp type, a mean of 8.5 years in those with the F type, and frequently more than 10 years in those with the S type. Endoscopy is generally used to determine the presence or absence of abnormal movement. In achalasia, the endoscope can be inserted into the stomach despite resistance at the stenotic site, and the mucosal surface is normal. Squamous cell carcinoma as a complication was observed in 21 patients (4.3%). The carcinoma complication rate was higher with a longer duration of disease and a longer observation period. The mean total course including the postoperative course was 27 years. Long-term and periodic X-ray and endoscopic observation of the disease course is important, and iodine staining is indispensable for early detection of esophageal cancer.