Respiratory symptoms and ventilatory capacity were studied in a group of 74 sewage workers employed in cleaning the city sewage system of Zagreb, Croatia. Workers were studied by their work stations: closed channels (N = 26), drainage (N = 31), and other sewage workers (N = 17). The prevalence of chronic respiratory symptoms was higher in closed channel and drainage workers than in controls, particularly for chronic cough (range: 41.9-46.2% vs. 14.3%), chronic phlegm (range: 38.7-46.2% vs. 14.3%), chronic bronchitis (range: 32.3-42.3% vs. 8.6%), and chest tightness (range: 29.0-53.8% vs. 0%). In the first two groups of sewage workers there was a high prevalence of acute symptoms which developed during the work shift, being particularly pronounced for eye irritation (range: 16.1-26.9%), dyspnea (16.1-23.1%), dizziness (range: 6.5-23.1%), throat burning (9.7-19.2%), and skin irritation (range: 22.6-26.9%). Baseline ventilatory capacity was significantly decreased compared to predicted values in sewage workers; in particular, values for FEF50 and FEF25 were reduced, suggesting obstructive changes in smaller airways. Our data indicate that sewage workers experience frequent acute and chronic respiratory symptoms and exhibit objective evidence of respiratory dysfunction.