Insulating barium titanate films were successfully grown on Ti‐deposited silicon substrates using the hydrothermal method. The film thickness was 35 and 49 nm for films treated at 200 and 250 °C, respectively, in a 0.25 M Ba(OH)2solution for 8 h. The BaTiO3films did not reach the Ti/Si interface. X‐ray photoelectron spectroscopy revealed OH‐free and nearly carbon‐free films, which was corroborated using Auger electron spectroscopy (AES) depth analysis. AES revealed that the oxygen and barium concentrations are correlated throughout the film, and the existence of a diffuse BaTiO3/Ti interface. A discussion on the film growth mechanism is made using existing information on the subject.