Background: Surgical myotomy is a well-established and validated method to treat severe gastro-oesophageal motor disorders such as achalasia. The benign character of these diseases further substantiates the importance of operating with greatest possible safety margins. We presently report our experiences with the use of perioperative leakage testing. Materials and Methods: Thirty-seven consecutive patients are reported of whom 30 had a laparoscopic, 3 a thoracoscopic and 4 an open operation. The indications for an operation were in 3 patients oesophageal spasm, in 30 patients newly diagnosed achalasia and 4 patients had an open reoperation due to a previous incomplete myotomy plus epiphrenic diverticulum. Thirty patients had a perioperative endoscopy with gas insufflation and a leakage test, whereas the others did not. Results: A previously unrecognised oesophageal mucosal tear was discovered during the test and repaired in 4 of the 30 tested cases whereafter everyone had an uneventful postoperative recovery. Among the remaining 7 untested patients, 3 developed clinical signs of leakage of whom 1 had an immediate reoperation. The postoperative courses were in all those prolonged and complicated. Conclusion: Perioperative use of endoscopy at the time of completion of the surgical myotomy is a useful tool to document leakage. Thereby the safety profile of the operation can be further enhanced.