A model Pd/Fe2O3 catalyst prepared by the vacuum technique has been studied in the carbon monoxide oxidation in the temperature range of 300-550 K at reagent pressures P(CO)= 16 Torr, P(O-2)= 4 Torr. It has been shown that the activity of the fresh catalysts is determined by palladium. According to the XPS data, the reduction with carbon monoxide results in the formation of Fe2+ (formally Fe3O (4)) and appearance of the catalytic activity in this reaction at low temperatures (350 K). High low-temperature activity of the catalyst is supposed to be connected with the reaction between oxygen adsorbed on the reduced sites of the support (Fe2+) and CO adsorbed on palladium (COads) at the metal-oxide interface.