Forty-five patients (20 men and 25 women) with a median age of 46.5 years, who were diagnosed with esophageal achalasia by clinical history, esophagoscopy, and barium esophagogram, underwent thoracoscope-assisted Heller myotomy with a minimal incision. Esophageal pressure and pH were monitored. Two patients were excluded because of mucosal perforation during the operation, requiring conversion to an open procedure. There was no postoperative esophageal leakage or hospital death. All patients resumed a normal diet as soon as gastrointestinal function recovered, and their symptoms disappeared completely. The mean operative time was 1.2 hours (range, 0.5-3.8 hours). After 2.1 years of follow-up, the outcome was rated excellent in 33 (77%) patients, good in 7 (16%), and fair in 3 (7%). Esophageal dilation was required in 3 patients because of relapsing dysphagia within 3 months after the operation. Four (9%) patients had some regurgitation but no further surgical or medical treatment was needed. Esophageal pressure and pH correlated with the clinical manifestations. Our modified Heller myotomy with the assistance of thoracoscopy is effective for achalasia.