Zirconia-based materials, with very low or null doping contents (YO(1.5) between 0% and 4% mol), were prepared in the form of bulk nanostructured materials through a two-step process. Nanometric powders of size-stabilized tetragonal zirconia were synthesized by the Pechini method and subsequently densified using the high-pressure field-assisted rapid sintering method at temperatures around 850 degrees-900 degrees C for 5 min under a pressure of similar to 800 MPa. By this method, theoretical densities of similar to 98% were achieved while retaining the grain size in the final product between 40 and 50 nm. The transition to the thermodynamically stable monoclinic phase was consequently prevented, allowing for the first time the synthesis of size-stabilized zirconia in a high-density bulk form.