Background: Microscopic fungi are the biological agent of occupational risk in the woodworking environment. Microbiological and chemical methods were used for determination of their concentration and species composition in dust. Material and Methods: Dust was sampled in 3 factories producing furniture using different materials. The 1st factory (A) processes solid wood, the 2nd (B) – chipboards and the 3rd factory (C) uses both wood and wood composites. The samples were collected in 12 different workstations and locations in each factory. The quantitative content of fungal biomass was determined basing on analysis of ergosterol (ERG). The species composition of fungi was analyzed using the microbiological method basing on culture morphology. Results: The concentration of ergosterol was relatively low and ranged from 0.012 mg/kg to 3.36 mg/kg. The average value of ERG amounted to 1.25 mg/kg in factories A and C and 1.15 mg/kg in factory B. The most frequently isolated fungi in factory A and B were Penicillum and Aspergillus. However, in the factory C, only Trichoderma was isolated. The maximum concentration of fungi in dust collected in factory B was 2377 cfu/g and it is 3 times more than in the dust from factories A and C. Conclusions: Workers of furniture factories may be exposed to airborne fungi associated with the wood dust posing health hazard. The content of these fungi is relatively small (ERG – max: 3.36 mg/kg) but the species, especially genera Penicillum and Aspergillus, found in the dust which were reported as having allergic and toxic properties. Med Pr 2014;65(6):705–713