The study, concerned with the biological properties of light soils, was carried out in the year 2000 in the area of the Roztocze National Park, its protective zone, and productive areas, on light soils that are in agricultural use (potatoe cropping). Soil samples were collected from the same places in May and September in order to examine changes in the number of soil microflora and activity of microflora. The highest biological activity was observed in light soils in the productive areas, lower biological activity was characteristic for the soils in the protective zone, and the lowest biological activity was found in the soils situated in the RPN. The number of micro-organisms and activity of the enzymes (dehydrogenase and catalase) were positively correlated with the contents of organic carbon. Activity of the enzymes was positively correlated with the number of fungi colonies, and bacteria and actinomycetes. The results of the analysis of biological properties of the soils reveal that there was little anthropopressure on the soil environment of the protected areas, which shows great ecological awareness of the local population.