Polycrystalline double perovskite Sr2FeMoO6 nanosized powders have been prepared using a wet chemical coprecipitation method of synthesis. The products were ignited in nitrogen at different temperatures in order to examine thermal evolution of precursors. Powders that were fired at an above 850degreesC for two hours have almost a single-phase structure. Some intermediate phases have been found at low temperatures. Powder X-ray diffraction linewith measurements show an average particle size in the order of 40 nm for samples annealed in 600-1000degreesC. It is suggested that the samples annealed at these temperatures were both simultaneously paramagnetic and ferromagnetic in nature. The advantages of this method are the low temperature involve in the sample preparation and the use of a non-reducing atmosphere. (C) 2005 Springer Science + Business Media, Inc.