s u m m a ry. The effect of addition of superabsorbent "Agro Bio Sorbent" on some physical properties of soil material formed from loess was investigated. The dose of superabsorbent ranged from 1 to 50 weight percent. The porosity (estimated from mercury porosimetry data), density (from helium pycnometer data) and the specific surface area (from the BET method, applied to water adsorption data) we re evaluated. The physical properties of the investigated soil -superabsorbent mixtures depended on the properties of both components, as well as on the mixture composition. The influence of the superabsorbent "Agro Bio Sorbent" was more visible in the case its higher concentration in the soil material. It was observed that with the increase of its content, the amount of micropores changed, the amount of mesopres decreased, the specific surface area increased and the density of the solid phase slightly decreased. From the point of view of a plant growth, the change of the air conditions and of the specific surface area is positive. However, the increase of the total volume of micropores is rather negative, because water confined to these pores is unavailable for plants. It should be also remembered that the mercury porosimetry does not provide information about macropores and about wide capillary pores.