Method to directly synthesize crystalline ZnCdO nanoparticles in an atmospheric-pressure microwave plasma is presented. The advantages of rapid synthesis within a few seconds and of template- or catalyst-free synthesis provide a chance of practical production and application of ZnCdO nanoparticles. Oxygen microwave plasma evaporated cadmium and zinc granules instantaneously and produced ZnCdO nanoparticles through explosive oxidations of Cd and Zn molecules with oxygen radicals. The structural characteristics and morphologies of as-synthesized samples were observed by XRD, SEM and TEM. The distribution of Zn, Cd, and oxygen species in as-produced sample was also investigated by the chemical composition mapping through EDX. (c) 2007 Elsevier B.V. All rights reserved.