Studies on surface modification of synthetic magnesium silicates were presented. Magnesium silicate was obtained by precipitation reaction using solutions of magnesium sulphate and of sodium metasilicate. In the course of the synthesis, the reactive system was supplemented with agents capable of modifying the surface of synthetic magnesium silicate. For the purpose appropriate amounts of silane proadhesive compounds and of non-ionic surfactants were used. For the so obtained products physicochemical parameters were established, such as bulk density, capacity to absorb water (wettability with water), capacities to absorb dibutyl phthalate an paraffin oil, elemental composition, particle diameters, specific surface area and sedimentation tendency.