Background. Heller myotomy has recently proved to be an efficient primary therapy in patients with achalasia, especially in younger patients (< 40 years of age). The results of laparoscopic myotomy cannot be finally assessed - on account of the shorter postoperative follow-up. The aim of our study was a 20-year analysis of the conventional cardiomyotomy as a standard for minimal-invasive surgery. Patients and methods. Within 20 years (Sept. 1985 - Sept. 2005), 161 operations for achalasia were performed in our clinic. Enrolled in this study were 108 patients with a conventional, transabdominal Heller myotomy in combination with an anterior semifundoplication (Dor procedure) and a median follow-up of 6 months. All patients were prospectively followed and besides radiological and manometrical examinations of the esophagus, the patients were asked for their clinical symptoms by structured interviews in two-year intervals. Results. The median age at the time of surgery was 44.5 (14-78) years, 72.2% of the patients were males. The median length of the preoperative symptoms was 3 years (3 months-50 years), the postoperative follow-up was 55 (6-206) months. In 70 (64.8%) patients, a pneumatic dilation had been performed. The preoperative Eckardt score of 6 (2-12) could be reduced to 1 (0-4) after Heller myotomy (p<0.0001). Consequently, with 97.2% of all patients a good to excellent result was achieved in the long-term follow-up, corresponding to a clinical stage I-II. Postoperatively, 69 patients (63.9%) gained weight. The radiologically measured maximum diameter of the esophagus decreased from preoperatively 45 (20-75) to postoperatively 30 (20-60) mm, while the minimum diameter of the cardia increased from 3.4 (1-10) mm to 10 (5-15) mm. The resting pressure of the lower esophageal sphincter could be reduced from 28.4 (9.4-56.0) mmHg to 8.6 (3.0-22.5) mmHg. Conclusion. Conventional Heller myotomy leads in the long-run with high efficiency to an improvement of the symptoms evident in achalasia. These results are to be regarded as standard for the assessment of the minimal-invasive procedure.