BACKGROUND & AIMS: Patients with achalasia are treated with either pneumatic dilation (PD) or laparoscopic Heller myotomy (LHM), which have comparable rates of success. We evaluated whether manometric subtype was associated with response to treatment in a large population of patients treated with either PD or LHM (the European achalasia trial). METHODS: Esophageal pretreatment manometry data were collected from 176 patients who participated in the European achalasia trial. Symptoms (weight loss, dysphagia, retrosternal pain, and regurgitation) were assessed using the Eckardt score; treatment was considered successful if the Eckardt score was 3 or less. Manometric tracings were classified according to the 3 Chicago subtypes. RESULTS: Forty-four patients had achalasia type I (25%), 114 patients had achalasia type II (65%), and 18 patients had achalasia type III (10%). After a minimum follow-up period of 2 years, success rates were significantly higher among patients with type II achalasia (96%) than type I achalasia (81%; P < .01, log-rank test) or type III achalasia (66%; P < .001, log-rank test). The success rate of PD was significantly higher than that of LHM for patients with type II achalasia (100% vs 93%; P < .05), but LHM had a higher success rate than PD for patients with type III achalasia (86% vs 40%; P = .12, difference was not statistically significant because of the small number of patients). For type I achalasia, LHM and PD had similar rates of success (81% vs 85%; P = .84). CONCLUSIONS: A higher percentage of patients with type II achalasia (based on manometric tracings) are treated successfully with PD or LHM than patients with types I and III achalasia. Success rates in type II are high for both treatment groups but significantly higher in the PD group. Patients with type III can probably best be treated by LHM. Trialregister.nl number NTR37; ISRCTN56304564.