Blown sands of the Borská nížina lowland are a unique ecosystem unknown from the viewpoint of microbiology. During the years 2002–2005 we studied the representation of physiological groups of soil microorganisms, their biomass, respiration and genus-species composition in the sites Mláky 1, 2 and sand dune Borová. Microbiological analyses confirmed that the studied soils have unfavourable life conditions. Total biomass of microorganisms, their respiration activity and qualitative representation showed very low values.