New data on the structure of silicon-containing oxide layers SiO2+TiO2 on titanium formed by the method of plasma electrolytic oxidation (PEO) as well as on the structure and catalytic activity in CO oxidation of MnOx+SiO2+TiO2/Ti composites formed on their basis using impregnation and annealing methods have been obtained. It has been demonstrated that silicon and titanium are rather homogeneously distributed over the SiO2+TiO2 coating bulk. The coating outer part is silicon-enriched titanium-depleted. The MnOx+SiO2+TiO2/Ti composites catalyze the CO conversion at temperatures above 100°C. Nanowhiskers consisting predominantly of manganese oxides have been found on the surface of the MnOx+SiO2+TiO2/Ti composites.