Modification of the applied Pt-containing catalysts with rare-earth metals is one of effective ways to increase their activity and resistance to thermal deactivation, which is associated with both an increase inthermal stability of the texture and structure of the carrier material and an increase in the degree of dispersion and resistance to sintering of the applied platinum metals (PM) when exposed to high temperatures. Conflicting data make it difficult to select a suitable modifier for the use as part of a three-waycatalyst in the exhaust treatment system of gasoline-powered cars, whose function is to simultaneouslyconvert CO, CxHy and NOx. In this work, the effect of europium-modified Pt-containing γ-Al2O3 -basedcatalyst on its physicochemical properties and activity in the oxidation of CO, CxHy, and NOx reductionprocesses was evaluated. The catalytic activity was evaluated by passing a gas mixture simulating theexhaust of a gasoline-powered car through the catalyst applied onto the surface of a cylindrical honeycomb block with simultaneous measurement of the degree of conversion of toxic components into relatively non-toxic CO2, N2 and H2O in the temperature range from 1000C to 4000C. The modification ofthe Pt/γ-Al2O3 catalytic system with europium was shown to enhance the activity in all three reactionsstudied, indicating a great potential for the use as a modifier of a three-way catalyst.