OSC properties and catalytic activities of Pt/ceria-zirconia catalysts with a small amount of platinum and cerium were investigated so as to reduce the usage of rare metals. In the case of Pt/CZ catalysts calcined at 800 C, the nano-sized platinum particles highly dispersed on the surface of CZ support. The platinum particles sintered via the calcination at 1000 C, whereas the mean diameters of Pt particles in Pt/CZ with small Pt loadings were maintained in nano-scale size. The enhancement of oxygen release properties due to Pt loadings was confirmed through H2-TPR measurements. On the other hand, the activities for CO oxidation were also improved by the loading of dispersed platinum particles. Moreover, the temperature of total CO oxidation was correlated with the oxygen release temperature. It was suggested that the release of lattice oxygen in ceria-zirconia support should be indispensable for CO oxidation reaction. This study revealed the effectivity of a small amount of Pt loadings and Zr rich CZ support. 2013 Elsevier B.V. All rights reserved.