Nanocrystalline zirconia (ZrO(2)) powders doped with 0.5 up to 5 mol% europium (Eu(3+)) were prepared by hydrothermal process using ZrCl(4) and EuCl(3)center dot 6H(2)O as starting materials. Optical emission and vibrational properties of as-prepared and calcined samples were investigated by phonon sideband (PSB), Fourier transform infrared (FT-IR) and photoluminescence spectroscopy as well as lifetime measurements. We found that the doping degree had a strong effect on the crystalline phase, m-and t-ZrO(2), of the host material, which also influenced on its shape and intensity of the PSB spectra. Residual water in the as-prepared samples indicated by FT-IR spectra induced water relating vibrations in the PSB spectra. The obtained PSB were compared with the peaks in the recorded FT-IR spectra and related to the vibrational modes of m-and t-ZrO(2).