ABCTRACT Introduction & Objective: Chronic respiratory diseases are the most prevalent late sequels of sulfur mustard gas injury among Iranian chemical warfare victims. Chest physiotherapy is one of the useful methods in care, cure and infection prevention of these patients. The aim of this study was to determine the short-term effect of chest physiotherapy on spirometric indices in chemical warfare victims exposed to sulfur mustard gas. Materials & Methods: In this study, 27 of the chemical warfare victims with respiratory diseases were selected. Chest physiotherapy including postural drainage percussion and vibration were used in four positions for all patients. Pulmonary function test (PFT) was obtained before (baseline), immediately and 20 minute after the chest physiotherapy. The SPSS software was used for the data analysis of the collected data. Results: Results of this study showed the significant effect (p<0.01) of chest physiotherapy upon forced expiratory volume in first second (FEV1) (baseline mean, 44.19 immediately after intervention mean 47.3 and 20 minute after intervention mean 48.3) and forced vital capacity (FVC) (baseline mean, 69.37 immediately after intervention mean, 73.67 20 minute after intervention 75.74). Chest physiotherapy had significant effect (p<0.01) in asthmatic bronchitis group and also had significant effect (p<0.05) in both severe and moderate groups. Conclusion: Chest physiotherapy was able to improve pulmonary function test indices in chemical warfare victims suffering from respiratory problems. The effect on asthmatic bronchitis group, as well as both severe and moderate groups, was significant.