BACKGROUND The Heller-Dor operation has recently been proposed for the treatment of esophageal achalasia even via a laparoscopic approach. METHODS To measure the medium-term effectiveness of this new minimally invasive technique, an evaluation of pre- and postoperative symptoms, esophagogram, endoscopic findings, esophageal manometry, and pH monitoring was prospectively designed in 43 patients with primary esophageal achalasia. The mean clinical follow-up for all the patients is 12 months (range 3-43), while the mean radiological follow-up is 11 months (range 1-23). Endoscopic data 1 year after surgery are currently available for 27 patients (63%), whereas a 12-month (range 1-26) functional follow-up (including manometric and pH-monitoring studies of the esophagus) is currently available for 35 patients (81.4%). RESULTS No dysphagia was reported in 38 cases (88.4%); two (4.6%) complained of occasional swallowing discomfort which regressed spontaneously; two (4.6%) had persistent dysphagia which regressed with pneumatic dilatation. One patient (2.8%) reported mild occasional dysphagia after a 1-year asymptomatic period. Preoperatively, esophagograms showed an average maximum diameter of 40.6 +/- 9.1 mm which decreased to 24.1 +/- 6.0 mm after operation. Mean lower esophageal sphincter (LES) resting and residual pressures decreased significantly from 28.6 +/- 10.7 mmHg to 8.8 +/- 4.1 mmHg and from 17.0 +/- 9.7 mmHg to 4.7 +/- 4.0 mmHg, respectively (p < 0.0001). These effects on esophageal diameter and LES function seem to persist over time. The complete absence of any peristaltic contractions recorded preoperatively in all cases remained unchanged after surgery in all but four patients. However, this rare recovery of peristalsis proved to be transient, and patients revealed a manometric impairment of their esophageal body function, but without complaining of dysphagia. Twenty-four-hour pH monitoring showed abnormal gastroesophageal reflux episodes in two (5.7%) of the 35 patients who were monitored: one was asymptomatic; the other had heartburn and endoscopically demonstrated grade II esophagitis. CONCLUSIONS Laparoscopic Heller-Dor operation achieves excellent medium-term results which, together with the already-demonstrated advantages of a minimal surgical trauma and rapid convalescence, validate the use of such a minimally invasive approach to treat patients with primary achalasia of the esophagus.