Zirconia nanomaterials, usually doped with trivalent ions, are widely used in the development of ceramic materials, sorbents, catalyst supports and biocompatible luminescent nanoprobes. Fluorescent zirconia-based nanoparticles, with and without arsenic and/or cysteine, were prepared at room temperature by a precipitation procedure in 1,2-ethanediol aqueous solutions. The prepared zirconia nanoparticles were characterized at several temperatures by XRD, SEM/ED-XRS, Raman spectroscopy, FT-IR, optical spectrophotometry and fluorescence microscopy. The zirconia-base nanoparticles treated at 873 K showed a pure tetragonal phase with crystallite sizes around 18 nm. The presence of arsenic and cysteine in the ZrO2 nanoparticles facilitated the emission of fluorescence, even after thermal treatments at 873 K. However, the As-doped and Cyst-capped nanomaterial treated at 1373 K produced less-fluorescent monoclinic zirconia nanoparticles, with crystallite sizes larger than 20 nm. Comments about the stabilization mechanism of the crystallographic phases of the zirconia nanoparticles were also outlined.