Occupational hazards and consequent health problems suffered by drivers in the public transport sector require preventive measures. The aim of this study was to assess the exposure of drivers to microbiological air contamination (airborne bacteria and fungi) in buses. The air in public transport vehicles was examined in autumn, winter and spring. To evaluate the exposure of drivers to bioaerosols, air samples were collected and examined for the total number of bacteria and fungi in the air, the number of mesophilic aerobic bacteria specified by the number of colony forming units (CFU) per 1 m³ of air. The results of the research show that public transport as a workplace can be considered to be a significant risk to health.