The stability of three-phase systems consisting of oil and a solid phase dispersed in aqueous solutions is examined. To achieve a sufficiently hydrophobic surface of the solid particles, the surface of glass microspheres was modified with ionic surfactants. The destabilization kinetics profile was determined and the instability index (TSI) was calculated for each sample. In an oil-free system, destabilization occurred very fast and there were no significant temporal profile changes for the samples modified with both cationic and anionic surfactants. For particles modified with cationic surfactant after the addition of oil, a decrease in TSI values with increasing surfactant concentration was observed as a result of oil agglomeration. Higher TSI values for bare particles modified with anionic surfactant reflected the behavior of oil droplets remaining in solution as they exhibit no attachment to the surface of glass beads.