Electrokinetic properties of the commercial titanium white (Tytanpol^® RS) and precipitated TiO₂-SiO₂ composite were studied. As they depend mainly on the character of the surface of materials studied, the effect of the amount and type of surface modifying agents on the electrokinetic potential was analysed. The study was performed on the commercial titania and TiO₂-SiO₂ composite precipitated from an emulsion system, both either unmodified or modified with three organofunctional silanes applied in three different concentrations. The effect of ionic strength of the electrolyte used (KCl, NaNO₃ or AlCl₃) on the electrokinetic potential of the two systems studied was established. Stability of the dispersive systems studied was evaluated.