Objective: To evaluate multidetector computed tomography (MDCT) findings in patients with achalasia, to assess its role in differentiating subtypes in detecting lung involvement and extra-esophageal thoracic complications. Subjects and Methods: This clinical retrospective study included 51 patients with manometrically confirmed achalasia who underwent chest X-ray and MDCT in diagnostic work-up. Esophageal wall thickness and morphology, luminal dilatation, lung changes, and extra-esophageal manifestations were analyzed on MDCT by 2 readers. Wilcoxon, Kruskal-Wallis and Mann-Whitney test were used for assessing the differences among the achalasia subtypes, and intra-class correlation coefficients (ICC) assessing the inter-observer agreement between the measurements of 2 readers. Results: Fourteen (27.5%) patients had achalasia subtype I, 21 (60.8%) had subtype II while 6 (11.8%) had subtype III. Esophageal wall thickness of the esophageal body (EB) and distal esophageal segment (DES) as well as nodular/lobulated appearance of DES were found significantly more often in subtype III (p = 0.024, p < 0.001, p = 0.009, respectively). Esophageal dilatation gradually decreased from subtype I to III (p = 0.006). Chest X-ray revealed lung changes in 9 (17%) and MDCT in 21 (41%) patients (p = 0.001), most frequently in subtype I, with predominance of ground-glass opacities. Tracheal/carinal compression was detected in 27 (52.9%) and left atrial compression in 17 (33.3%) patients. Excellent inter-observer agreement was observed in measuring the EB and DES wall thickness, and diameter of EB (ICC 0.829, 0.901, and 0.922). Conclusion: MDCT is a useful tool for detecting lung and extra-esophageal thoracic complications in patients with achalasia, and could be a valuable additional imaging modality in the differentiation of achalasia subtypes.