Octahedral BaWO4 microparticles have been prepared via a simple microemulsion-mediated hydrothermal procedure. The X-ray diffraction (XRD) pattern shows that the obtained octahedral BaWO4 microparticles are of the Scheelite structure. Select area electron diffractions (SAEDs) and high-resolution transmission electronic microscopy (HRTEM) identify that the octahedral BaWO4 microparticles are single crystal in nature. The influences of hydrothermal treating time and surfactant concentration on the formation of well-defined BaWO4 octahedral microparticles are studied. (c) 2005 Elsevier B.V. All rights reserved.