Background:Chronic pulmonary complication is the most common delayed toxic effect of sulfur mustard (SM) and it has no treatment so far.Objectives:To evaluate short-term therapeutic effects of inhaled tiotropium bromide and pulmonary rehabilitation on pulmonary function of patients with SM induced lung injury.Patients and Methods:In a randomized clinical trial, using convenient sampling method, 54 patients with chronic lung disease due to SM exposure were recruited in Baqiyatallah General Hospital, Tehran, Iran for a period of 2-month study. They were randomly divided into 3 groups of 18 participants each. Group 1 received routine drugs (Serevent, Flixotide), pulmonary rehabilitation 30 minutes/2 times a week, and tiotropium bromide 18 µg/day. Group 2 was treated with routine drugs and pulmonary rehabilitation and group 3 was only on the routine drugs. cardiopulmonary exercise test (CPET), plethysmographic measurements, and respiratory symptoms evaluation were performed before and after medical intervention.Results:In group 1, compared to group 3, significant differences were found with regard to symptoms of cough ([difference between the first and last visit in group 1: Diff 1] = -1.6, Diff 3 = -0.3, P = 0.01) and nocturnal dyspnea (Diff 1 = -1.9, Diff 3 = 0.0, P = 0.01), likewise, compared to group 2, significant differences were found with regard to lung function parameters of forced vital capacity (Diff 1 = 3.0, Diff 2 = -3.5, P = 0.03), forced expiratory volume in one second (Diff 1 = 3.9, Diff 2 = -5.6, P = 0.009), maximal mid-expiratory flow rate 25% - 75% (Diff 1 = 1.5, Diff 2 = -3.2, P = 0.007) and peak expiratory flow (Diff 1 = -2.06, Diff 2 = -4.3, P = 0.04). Total lung capacity (Diff 2 = 9.28, Diff 3 = -12.07, P = 0.02) and residual volume (Diff2 = 32.1, Diff3 = -27.6, P = 0.04) were increased in group 2 compared to group 3. There were no significant differences with regard to CPET results among all groups (P > 0.05).Conclusions:Inhalation of tiotropium bromide in combination with pulmonary rehabilitation could improve some plethysmographic lung volumes and clinical outcomes in patients with chronic pulmonary disease due to SM. Short-term prescription of pulmonary rehabilitation has no effect on CPET of patients.