Our research aimed to assess the impact of soil pollution with polycyclic aromatic hydrocarbons on the amount of plant biomass produced and the numbers of selected groups of soil microorganisms. The aromatic hydrocarbons supplied to the soil were decomposed to various degrees, but we discovered a considerable decrease in detectable PAHs in soil. In strongly polluted soils the detected amount was the lowest for fluorene, then for benzo(a)pyrene and finally for chrysene. The greatest amounts of maize biomass (the aboveground parts and roots) were assessed on the treatment, where soil revealed elevated PAH content (I). Introducing PAHs to the soil caused quantitative changes in the soil microbiocenotic composition. The numbers of bacteria, fungi and actinomycetes were greater in the soil from treatments polluted with PAHs (I and II) than in the control soil (K).