OBJECTIVE In the literature, reports on the definitive rate of cure of the surgical treatment of oesophageal achalasia are not numerous. The aim of this study is to assess the clinical-instrumental-based patient's outcome related to long-term follow-up. METHODS One hundred and seventy-four patients (80 men, median age 57 years, range 7-83) consecutively submitted to first instance transabdominal Heller-Dor in the period 1978-2002 were considered. Follow-up consisted of clinical interview, endoscopy, barium-swallow and oesophageal manometry if required. Twenty-six cases (15%) were sigmoid achalasias. RESULTS One patient died post-operatively (severe haemorrhage in a patient previously operated upon for a cardiovascular malformation and suffering for portal hypertension), 173 were followed-up (mean 109 months, range 12-288, median 93 months) of whom 68 for more than 15 years. On the whole 151 patients (87.3%) had satisfactory and 22 (12.7%) had poor long-term results. Seven out of 173 patients (4%), 6 of whom were pre-operatively classified as sigmoid achalasia, subsequently underwent oesophagectomy, 3 for epidermoid cancer, 1 for Barrett's adenocarcinoma, 2 for stasis oesophagitis and recurrent sepsis, 1 for severe dysphagia. Fifteen patients (8.7%) had an insufficient result due to reflux oesophagitis which appeared in 2 (one erosion) after 184 and 252 months. All 22 patients, whether surgically or medically retreated, achieved satisfactory control of dysphagia and reflux symptoms. CONCLUSIONS In the long term, insufficient results strictly related to Heller-Dor failure, always due to reflux oesophagitis, were recorded in 15/173 patients (8.7%) although it is questionable whether reflux oesophagitis appearing after more than 15 years is due to the Dor incompetence or to ageing. In sigmoid achalasia, oesophagectomy rather than myotomy should be taken into consideration in the first instance. In the long-term, surgery is the best definitive treatment for oesophageal achalasia.