A semi-colloidal technique was used to synthesize a precursor powder of zirconia-mullite composites using an aqueous suspension of sillimanite powder and zirconium oxychloride solution and adding micron sized aluminium powder to the precipitate (calcined) thus obtained. The precursor powder was compacted in presence of MgO and CeO2 additives and fired at different temperatures. The physico-mechanical properties of the sintered compacts were influenced both by the firing temperatures and the nature of additives present in the compacts. MgO was found to exert a greater influence on the physico-mechanical properties of the composites than CeO2.