A uniformly aggregated 3 mol% yttria-stabilized tetragonal zirconia nano-powder (3Y-TZP) was prepared using thermal hydrolysis and the ultrasonic deagglomeration technique. The possibility of nano-engineering of Pt-3Y-TZP composite aggregates was studied. The as-synthesized Pt nano-particles (similar to 2 nm) were impregnated into zirconia nano-aggregates (20-45 nm). The morphology manipulation technique allowed production of the composite zirconia-based aggregates in which a significant fraction of the Pt particles was embedded into the densified zirconia aggregates. Using the colloidal technique and low-temperature (1150 degrees C sintering, we prepared the Pt-zirconia (0.5-1.5 wt% of platinum) nano-composites with average 3Y-TZP grain sizes of 120 run, and with the platinum grains size in the range of 20-60 nm. The catalytic properties of composite Pt-3Y-TZP nano-composites were studied and described.