We propose a flame metal combustion method for continuously synthesizing metal oxide nanoparticles, Micro-sized metal powder precursors were injected into a hydrogen-oxygen flame through a newly designed feeder system in order to be completely converted into metal oxide nanoparticles with good crystallinity. There is no limitation in the selection of precursors including metal, metal chloride and metal organic powders to synthesize nanoparticles. Various oxides such as magnesia, iron oxides and zinc oxide were demonstrated to be successfully generated by using this method. The sizes of oxide nanoparticles were controlled by varying flame temperatures and residence times. (C) 2009 Elsevier B.V. All rights reserved.