Oxidation of antimony segregated surfaces of Fe-0.23at%Sb alloy was studied by XPS. After the concentration of the segregated antimony was controlled by heating the sample at 873 K, the surfaces were oxidized at room temperature, 473 and 673 K. The oxidation at room temperature was carried out through the successive stages of oxygen adsorption, antimony oxidation and iron oxidation, irrespective of the concentration of the segregated antimony. The amount of oxygen to initiate the oxidation of the antimony and iron increased with the surface antimony concentration. The oxidation at 473 K was similar to that at room temperature. In the oxidation of the surface with maximum segregation of antimony at 673 K, oxidation of the iron and disappearance of the antimony were observed after the oxygen had adsorbed.