Free-flowing Ln(2)Zr(2)O(7) microspheres (Ln = lanthanide) were prepared by an aqueous inorganic set-gel route without any intermediate phase formation. The gel spheres obtained at room temperature were shown by X-ray diffraction to be amorphous but calcination to 750 degrees C produced fully crystalline fluorite phases. On calcination to 850 degrees C, pyrochlore phases were formed with suitable lanthanides. The microspheres were characterized by X-ray diffraction and scanning electron microscopy with energy dispersive analysis of X-rays to give accurate determination of structure, composition and crystallite size.