The prevalence of acute and chronic respiratory symptoms and diseases as well as lung function changes were studied in 409 rubber male workers and 172 nonexposed control male workers. Ventilatory capacity was measured by recording maximum expiratory flow-volume (MEFV) curves on which forced vital capacity (FVC), one second forced expiratory volume (FEV1) and flow rates at 50% and the last 25% of vital capacity were calculated (FEF50, FEF25). A significantly higher prevalence of all chronic respiratory symptoms except asthma was found in rubber workers in comparison to the controls. Smokers had significantly higher prevalence of most of the chronic respiratory symptoms than nonsmokers. Rubber workers exposed for more than 10 years had also significantly higher prevalence of chronic respiratory symptoms than those with shorter exposure. A high prevalence of acute symptoms during work shift was recorded in rubber workers. Ventilatory capacity was mostly decreased during work shift, particularly FEF50 and FEF25. All acute reductions were greater in rubber workers exposed for more than 10 years as compared to those with shorter exposure. Alupent inhaled at the end of the work shift significantly improved decreased values. Rubber workers demonstrated significantly lower ventilatory capacity tests with respect to the controls. A large number of rubber workers showed a decrease in lung functions tests less than 70% of the predicted normal values. Our data suggest that rubber workers are exposed to numerous noxious agents which may lead to acute and/or chronic impairment of lung function.