We report the fabrication of platinum nanoclusters with a narrow size distribution on TiO2 nanoparticles using atomic layer deposition. With MeCpPtMe3 and ozone as reactants, the deposition can be carried out at a relatively low temperature of 250 degrees C. Our approach of working with suspended nanoparticles at atmospheric pressure gives precise control of the material properties, high efficiency of the use of the platinum precursor, and the possibility for large scale production of the nanostructured particles.