Nanostructured platinum/yttria-stabilized zirconia (YSZ) cermet (composite of ceramics and metal) is obtained by the sol-gel method. Influences of the processing parameters on the nanostructure are experimentally studied using X-ray diffraction, held emission scanning electron microscopy, electron probe microanalysis, and nitrogen adsorption. The nanostructure of-the cermet is controlled by the Pt/YSZ ratio, gelling procedure, and calcination temperature. The slower gelling or higher temperature calcination enlarges the YSZ grain size, The addition of a smaller amount of Pt or calcination at higher temperatures reduce the Brunauer-Emmett-Teller (BET) surface area when calcined at 973 K or above. The addition of a larger amount of Pt increases the porosity when calcined at 973 K or above. By controlling the conditions of synthesis, gelling, and Pt content, the average YSZ grain size was kept within 50 inn after calcination at 1173 K.