Background/Objective: Pulmonary complains (acute and chronic) are known complications of exposure to sulfur mustard gas that for evaluation of them multiple paraclinical methods as HRCT and spirometry were used. HRCT is preferred to plain chest X-ray and conventional CT scan because better detection of both parenchymal and airway abnormalities such as bronchectasia and air trapping. Expiratory HRCT is considered as the imaging modality of choice for evaluation of air trapping."nPatients and Methods: In this study we reviewed medical records of 36 patients with documented exposure to sulfur mustard in Iran-Iraq war in order to evaluate correlation between air trapping scoring and spirometric findings."nResults: In all HRCTs air trapping was present with score ranging from 2 to 18 and mean (±SD) was 7.5 (4.2) . Nineteen cases had score over than six that suggest bronchiolitis obliterans. Spirometric indices as patient FEV1, FVC, FEV1/FVC, MMEF and their percentage to mean values were obtained. We found no correlation between air trapping scoring and spirometric parameters according to r and p-values obtained by SPSS software. "nConclusion: HRCT can be diagnosed bronchiolitis obliterans in earlier stages than spirometry.