Influence of preparation conditions on the crystallization of yttria-stabilized zirconia was investigated, and for this purpose samples were prepared by sol-gel process and mechanochemical preparation. For the sol-gel process, the influence of the presence of alumina (0% and 20 %) and previous milling on crystallization was examined, while for the mechanochemical preparation influence of alumina content (10, 20 and 30 %) was studied. The powders were calcined at temperatures in 400 – 1200 °C range, while compressed tablets were calcined at 1400 °C. Crystallization of powders was monitored by X-ray diffraction analysis, Raman spectroscopy and simultaneous differential scanning calorimetry and thermogravimetric analysis. The morphology of the tablets was tested by scanning electron microscope, and their density was determined by Archimedes method. The presence of alumina was found to delay crystallization of zirconia, otherwise their crystallization is independent. Tetragonal zirconia and corundum crystallize as the final phases at 1200 °C. Milling affects the crystallization of the sol-gel powders since nuclei of further crystallization are formed. In case of mechanochemical preparation there is no influence of alumina content on powders crystallization. Because of less homogeneous initial powder, monoclinic zirconia is also eventually formed. The obtained tablets are porous, but there are no significant differences between the mechanochemical preparation and sol-gel process in pore size and the relative density of tablets. Mechanochemical preparation gives tablets with homogeneous morphology, while the advantage of the sol-gel process is preparation of pure tetragonal phase.