Successful preparation of strontium titanate (SrTiO 3 ; STO) thin films has been realized by the liquid phase deposition method. The STO precursor solid thin films with close-packed grains smaller than 200 nm were fabricated from an aqueous solution of Sr(NO 3 ) 2 /(NH 4 ) 2 TiF 6 /H 3 BO 3 =1/1/3 (molar ratio) at 50 o C on a Si substrate. X-ray photoelectron spectroscopy analysis showed that the as-deposited film contained fluorine as an impurity, which could be completely eliminated by annealing at 500 o C in air, accompanying the crystallization of the as-deposited amorphous thin film into perovskite-type STO.