Nanocrystalline sulfated zirconia powder was prepared by a non-alkoxide sol-gel route using acidic condition (pH 1-2). The samples had superfine crystallites and pure tetragonal phase at 700 degrees C. Zr(acac)(4) was used as zirconium precursor due to a better retention of sulfate species and H2SO4 0.5 M was used as sulfating agent. Fourier transform infrared (FT-IR) spectra have shown Zr-O-Zr and sulfate bonds. Crystal phase and crystallite size have been determined by X-ray Diffraction (XRD) analysis. Besides, the morphology of the samples has been investigated by field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). The optical properties of the samples have been analyzed using photoluminescence (PL) spectroscopy, too. All the analyses consistently have shown fairly uniform nanoparticles (calcined at 600 and 700 degrees C) with very small size and pure tetragonal phase with crystallite size between 5 and 10 nm. (C) 2010 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.