The paper presents results of investigations which aimed to test the effect of varying doses of effective microorganisms (EM) on basic physical and water properties of arable-humus horizons of mineral soils of different texture composition. The soil material for experiments was collected from two arable soils (subtype: proper black earth). Samples of impaired and intact structure intended for investigations were collected from pot experiments established under controlled conditions. The following parameters were determined in the examined soils: texture composition, soil density, solid phase density, total and drainage porosity, filtration coefficient, soil water binding potentials and useful retention. It was found that various EM doses exerted different influence on soils characterised by different texture. In general, such effect is advantageous for the soil but it always changes nearly all its physical and water properties (primarily: porosity, filtration coefficient, binding potential and water availability).