The addition of a Dor antireflux procedure reduces the risk of pathologic gastroesophageal reflux (GER) by ninefold following laparoscopic Heller myotomy for achalasia. It is not clear, however, how these benefits compare with the increased cost of the fundoplication. The objective of this study was to estimate the cost-effectiveness of Heller myotomy plus Dor fundoplication compared with Heller alone in patients with achalasia.We conducted a cost-utility analysis using the Markov simulation model to examine the two treatment alternatives. The model estimated the total expected costs of each strategy over a 10-year time horizon. Data for the model were derived from our randomized clinical trial. The strategies were compared using the method of incremental cost-effectiveness analysis.The incidence of pathologic GER was 47.6% (10 of 21 patients) in the Heller group and 9.1% (2 of 22 patients) in the Heller plus Dor group using an intention-to-treat analysis (p = 0.005). Heller plus Dor was associated with a significant reduction in the risk of GERD (relative risk 0.11; 95% confidence interval 0.02-0.59; p = 0.01). The cost of surgery was significantly higher for Heller plus Dor than for Heller alone (mean difference $942; p = 0.04), secondary to a longer operating room time (mean difference 40 min; p = 0.01). At a time horizon of 10 years, when proton pump inhibitor (PPI) therapy costs are considered, the cost-utility analysis demonstrates that Heller plus Dor surgery is associated with a total cost of $6,861 per patient and a quality-adjusted life expectancy of 9.9 years, whereas Heller-alone surgery is associated with a cost of $9,541 per patient and a quality-adjusted life expectancy of 9.5 years.In achalasia patients, Heller myotomy plus Dor fundoplication is preferred to Heller alone because it is both more effective in preventing postoperative GERD and more cost-effective at a time horizon of 10 years.