Abstract. LiNbO3 films were epitaxially grown on c-sapphire substrates using oxygen radical-assisted laser molecular beam epitaxy (MBE). X-ray diffraction-based structural analysis showed that the films were epitaxial. Triple-axis rocking curve measurements of the LiNbO3 (0006) reflection revealed that the film was highly c-oriented with an extremely narrow mosaic; the full width at half maximum of the LiNbO3 (0006) rocking curve was 0.0036, comparable to the value of high-quality bulk crystals. The surface of the film was very smooth, with a surface roughness r.m.s. value, measured by atomic force microscope, of 0.4nm for a film of thickness 15nm. The chemical composition of the film measured by X-ray photoelectron spectroscopy (XPS) was stoichiometric within the accuracy of XPS measurement.