Anisotropic monoclinic zirconia particles (aspect ratio of 4-10) have been prepared upon hydrothermal processing of 1,12-diaminododecane (DADD)-hydrous zirconia gels at pH of 14 and at 230 degrees C for 3 days. A biphasic growth model comprising melted DADD and the water/ethanol mixture is proposed to account for the generation of rod-like morphology.