In this study, we successfully synthesized monodispersed metal oxide nanoparticles of high-temperature phases such as monoclinic VO2, orthorhombic Ta2O5 under an ambient condition without any post-annealing process, applying the liquid phase deposition (LPD) method in the confined system of reverse micelle (RM). It was suggested that the obtained nanoparticles were highly crystallized due to the depression of surface disorder, indicated by Raman spectrum of rutile type SnO2 nanoparticles. This procedure represents a simple route for the production of highly crystallized nanoparticles with potentially interesting applications. (C) 2007 Published by Elsevier Ltd.