The main objective of the study was to assess particulate matter (PM) exposure levels for both the farmer and the veterinarian during different operational tasks in pig-fattening houses, and to estimate their exposure levels on a daily working basis (time-weighted average (TWA)). The measured PM fractions were: inhalable and respirable PM, PM10, PM2.5 and PM1. The effects of pig age, pen floor type (conventional or low emission surface) and cleaning of the pens on the personal PM exposure were also investigated. Indoor concentrations of NH3, CH4, and CO2 were additionally measured during some operational tasks. The results showed that personal exposure levels can become extremely high during some operational tasks performed by the farmer or veterinarian. The highest concentration levels were observed during feed shovelling and blood sampling, the lowest during the weighing of the pigs. For the farmer, the estimated TWA exposure levels of inhalable and respirable PM were 6.0 and 0.29 mg m(-3), respectively. These exposure levels for the veterinarian were, respectively, 10.6 and 0.74 mg m(-3). The PM concentration levels were mainly determined by the performed operational tasks. There was no significant effect of pig age, pen floor type, nor cleaning of the pens on the personal exposure levels.