Background. Laparoscopic Heller-Dor (LapHD) is an effective treatment for esophageal achalasia, with good results in about 90% of patients. It may be argued whether such an operation is appropriate in case of dilated, sigmoid-shaped megaesophagus. The aim of our study was therefore to evaluate if the esophageal diameter and the presence of a sigmoid-shaped megaesophagus could affect the outcome of LapHD procedure in patients with achalasia.Patients and Methods. From 1992 to October 2008, among 447 patients treated with LapHD for esophageal achalasia, 18 had a straight, larger than 6 cm in diameter esophagus (Group A, median age 47, range 19-80) and 15 had a sigmoid-shaped, larger than 6 cm in diameter esophagus (Group B, median age 43, range 18-78). These two groups formed the basis of this report. The findings of the remaining 414 patients, with the esophagus smaller than 6 cm in diameter, served as control group (Group C, median age 44, range 19-85). The percentage of patients who underwent a previous endoscopic treatment before the operation did non differ in the 3 groups (28%, 13% and 21% respectively for Group A, B and C, p=ns). Also other demographic and clinical parameters, such as symptom score or duration of symptoms, did not differ in the 3 groups. The operation was performed by 4 staff surgeons in a well standardized way, with the only addition of a wider isolation of the cardia in order to straighten the distal esophagus in the Group B patients. One patient in group A and 16 in group C experienced accidental mucosal perforation during surgery. Results. At a median follow-up of 30 months (IRQ 10.8-78.2) we obtained an excellent outcome in all but one of the Group A patients (94%). These results were similar to those obtained in Group C patients (382/414 good results, 92%), whereas in Group B only 9 patients out of 15 (60%) were relieved of their dysphagia (p<.01, Chi-square test). Two redo-myotomies and 2 esophagectomies were eventually required in 4 patients; other 2 patients are still undergoing periodical endoscopic dilations. Only 1 patient in group A required complementary dilations.Conclusions. In patients with a dilated (> 6 cm) but non-sigmoid in shape esophagus, LapHD allows results similar to those obtained in patients with earlier disease. In patients with late disease and a sigmoid-shaped esophagus, LapHD may still achieve good results by releaving dysphagia in more than half of the patients (60%). Therefore, laparoscopic myotomy may still be the first surgical option to be offered to these patients before esophagectomy.