A study of workers' exposure to airborne culturable bacteria was performed at the wastewater treatment plant in Myszków. A six-stage Andersen impactor was used to carry out measurements. The concentrations of total bacterial aerosols ranged from 10(2) to 10(3) CFU/m3 and were lower than the proposed standards. The results of the study show that Gram-negative bacteria contributed to about 35% of the total bacterial aerosol. The largest part of the airborne Gram-negative bacteria constituted Enterobacteriaceae. Pathogenic bacteria found in the air: were as follows: Aeromanas hydrophila, Enterobacter agglomerans, Yersinia enterocolitica, Escherichia coli and Streptococcus faecalis. The microbiological contamination of the air was highest near the aeration basin. Exposure to airborne culturable bacteria may cause respiratory and gastrointestinal symptoms among sewage workers. It is necessary to reduce the exposure to airborne bacteria at this phase of the process of wastewater treatment.