The adsorption and electrokinetic properties of the mixed oxide CuxOy–SiO2 in the absence and presence of poly(vinyl alcohol) – PVA were examined. Three solids differing with the CuxOy content were applied (0.2; 1 and 3 mmol/g SiO2, respectively). The polymeric substance (100 kDa) was characterized with the acetate groups hydrolysis degree equal to 86%. Adsorption, solid surface charge and zeta potential measurements for all types of adsorbents were carried out as a function of solution pH (3–10). The obtained results indicated that the PVA adsorption amount strongly depends on the solution pH. The higher solution pH value is, the more polymer macromolecules are adsorbed on the solid surface. Moreover, the adsorption level of polymer increases with the rise of CuxOy content in the mixed oxide. The lack of the changes in the solid surface charge density due to the polymer addition proved that hydrogen bridges interactions are mainly responsible for PVA adsorption.