Respiratory symptoms and ventilatory capacity were studied in a group of 70 subjects employed as sewage workers. It was found that exposed workers had an increase in the prevalence of chronic respiratory symptoms when compared with control workers, although the difference was statistically significant only for chest tightness (p less than 0.01). In exposed workers there was a high prevalence of acute symptoms which develop during the shift being particularly pronounced for eye irritation, dyspnea and cough. A large number of sewage workers complained of skin disorders. Results of lung function testing demonstrated reduction of FEV1, FEF50 and FEF25 in relation to predicted normal values suggesting obstructive changes mostly located in smaller airways. Our data confirm that sewage workers are exposed to different occupational noxious agents which may lead to the development of chronic lung function changes.