Yttrium oxide (yttria) nanoparticles were successfully synthesized by co-precipitation method. As-synthesized and annealed powders were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), UV visible (UV vis), photoluminescence (PL) spectra and Fourier transform infrared spectrometer (FOR). The XRD results show that the as-prepared sample has mixed phase of Y(OH)(3) and yttria (Y(2)O(3)). However, cubic yttrium oxide phase alone is found for annealed samples. The strain values are calculated from Williamson Hall (W H) plot for annealed samples. SEM and TEM micrographs show that the samples are composed of aggregated nanoparticles with different shapes and sizes. From the UV vis spectra, it is found that the position of the absorption peak is shifted towards the lower wavelength side when particle size decreases. In the PL spectra, the broad emission bands are observed between 340 and 380 nm and the presence of metal oxide is confirmed by FTIR spectra. (C) 2010 Elsevier Ltd. All rights reserved.