Iraq has used extensively chemical warfare agents in recent Iran-Iraq conflict (1980-1988) and it is believed about 450,000 people were exposed to this agents. Long-term effects of chemical warfare agents, particularly mustard gas, on pulmonary function tests (PFT) (VC, FEV1 , FVC, FEV/FVC, PEF, MEF50%, MEF25%, MEF25-75% , ERC and IC) are estimated during 7.7 [standard deviation (SD)=l.2] years of follow-up. Between March and November 1994, we have selected 292 chemical warfare exposed victims from the present files in the Kerman branch of Iranian Foundation of War Casualties. Age, occupational exposure, cigarette smoking, weight and height was recorded. The mean (SD) age of participants was 31.5 (8.6%) years at examination time. 250 (85.6%) of victims developed acute clinical manifestation of pulmonary dysfunction immediately after attack and more than half of them (160; 54.8%) have pulmonary dysfunction in PFT, 5-10 years after exposure. In PFT, 39(13.3%) had restrictive pattern, 109 (37.3%) had obstructive pattern and 12 (4.1 %) had mixed pattern, 132 (45.2%) had normal PFT. Decreased vital capacity was statistically significant (P<0.05). The incidence of late complications was higher in persons with acute clinical manifestations of pulmonary dysfunction immediately after attack. The vital capacity of victims who used mask and protective covers was higher (P<0.05).