This paper focuses on the development of ceria-zirconia materials which have high thermal stability and high catalytic activity. The CeO 2 -ZrO 2 system is very important as a sub-catalyst in the autoexhaust catalytic converters, especially on the oxygen-storage capacity (OSC). The role of the CeO 2 -ZrO 2 is to adjust the air-fuel ratio to the stoichiometric value to attain the simultaneous conversions of the three main pollutants such as CO, NO x and hydrocarbons, by providing and absorbing oxygen during fuel-rich and fuel-lean conditions, respectively. In this article, recent advances in the design and development of the sub-catalysts in the autoexhaust catalytic converters are reviewed.