Nanocrystalline complex oxides have been synthesized by combination of sol–gel auto combustion and ultrasonic irradiation techniques using copper nitrate, zinc nitrate as metallic nitrates and glycine, urea and thiourea as fuels. Sol-gel combustion (combination of the chemical sol–gel process and the combustion process) as a proper synthesized technique is used to synthesize ZnO/CuO nanocomposites. This method is based on the gelling and further combustion of solution in aqueous phase which contain salts of the desired metals and fuels. Consequently, ZnO/CuO powders were prepared with molar ratio of nitrates to fuels 1:2. Combustion process is inexpensive since it does not involve intermediate decomposition and/or calcining steps. Combustion process ends, within 30 seconds for all systems.. Finally, the product powder was characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM).