OBJECTIVE: Pesticide aerosols are frequently toxic irritants associated with respiratory symptoms and lung function impairment. METHODS: A cross-sectional study examined the prevalence of acute and chronic respiratory symptoms and lung function abnormalities in 82 workers employed in processing pesticides and in 60 control workers not exposed to irritants and employed in a soft drink bottling plant. RESULTS: The prevalence of almost all chronic respiratory symptoms was greater among pesticide workers than among controls. A logistic regression analysis shows differences between men and women. There was a high prevalence of acute symptoms during the work shift in pesticide workers. The data on ventilatory capacity indicates significant reductions in all tests compared to predicted. Multivariate analysis of lung function showed differences in smoking and work exposure effects in men and women. CONCLUSION: Our data indicate that duration of work exposure in the pesticide processing industry may be associated with the development of acute and chronic respiratory symptoms and lung function changes. These effects appear to be aggravated by smoking.