OBJECTIVE Contamination of feeds with pathogenic microflora and mycotoxins constitutes a serious threat both for animals and humans. The aim of the study was to determine the degree of risk of the occurrence of microscopic fungi, selected bacteria and mycotoxins from the trichothecene group in poultry feeds in western Poland. RESULTS In feed mixtures, the concentration of ergosterol (ERG), being a specific quantitative biomarker for the content of microscopic fungi, was determined. Grower and finisher feeds were characterized by a higher count of bacteria and fungi in comparison to starter feeds. A considerable variation was found in the amount of ergosterol in analyzed feeds. Mean ergosterol content in feeds amounted to 19.34 mg/kg. The most common genera of fungi detected in the tested feeds included Aspergillus, Rhizopus and Mucor. Irrespective of the type of feed, the proportion of trichothecenes group B was five times higher than that of trichothecenes group A in relation to the total content of these mycotoxins in samples. In terms of the analyzed mycotoxins, feeds contained the highest concentration of deoxynivalenol (DON). A statistically significant correlation was shown between DON and ERG and between total trichothecenes and ERG. CONCLUSION Recorded results indicate that the level of microbiological contamination in feeds for broiler chickens produced in western Poland is within the requirements of the binding standards.