In this work, the effects of selected polymers on zirconia crystallization under hydrothermal conditions were examined. The powders were crystallized by using different precursors, mineralizers, crystallization time and temperature. The resultant chemical composition, phase composition and morphology of the powders have been examined using SEM, TEM, XRD and XRF methods. Depending on the conditions of crystallization, the zirconia powders showed different morphologies i.e. 3D assemblies of plate-like or needle-like grains and hollow agglomerates. TEM revealed plate-like and needle-like particles that were composed of smaller primary plates of about 100nm in size. The crystallization of an unknown phase composed of zirconium, oxygen, sodium and fluorine is reported.