An autostoichiometric vapor gel deposition approach is demonstrated for ferroelectric LiTaO3 and LiNbO3 thin films. This approach utilizes the partial hydrolysis of hygroscopic alkoxide in the vapor phase, and the subsequent polycondensation on a heated substrate. Epitaxial films with precisely controlled stoichiometry were obtained. Ultra low temperature deposition was achieved taking advantage of the inherently low temperature sol-gel chemistry. The vapor phase hydrolysis of alkoxides provided a mild deposition reaction that allows for the autostoichiometric deposition. The vapor gel method appears to possess the combined advantages of sol- gel processing and MOCVD.