Abstract: A hydrothermal process for making barium titanate powders. The process utilizes a thawed hydrated titanium oxide gel as a titanium source for the hydrothermal reaction. The process includes mixing the thawed hydrated titanium oxide gel and a barium source in a reaction chamber to form a hydrothermal reaction mixture. The temperature of the hydrothermal reaction mixture in the reaction chamber is increased to a reaction temperature to form a barium titanate particle suspension. The particle suspension is then cooled to room temperature. The resulting barium titanate particles, preferably, have a submicron particle size.