The ability of the cubic phase of zirconia to accommodate in solid solution the oxides of rare earth elements with differing cationic radii has been investigated. Mixed oxide phase assemblages were prepared by hydrolysing zirconium butoxide with solutions of rare earth element nitrates followed by drying, calcining and sintering. The resulting products were characterised by X-ray diffraction and energy dispersive spectroscopy. The cubic zirconia phase can accept into solid solution the larger, non-cubic stabilising, rare earth element ions such as lanthanum in the presence of the cubic stabilising oxides of yttrium and samarium. As the proportion of the larger rare earth element ions is increased the formation of pyrochlore type compounds is favoured.