TiO2-SiO2 (Ti : Si = 50 : 50 mol%) films were prepared by the sol-gel process with and without organic ligands as modulators, The effect of the ligands on the crystal structure and optical properties of the films was studied. In all samples, the anatase structure of TiO2 appeared between 500 degrees C and 700 degrees C. The crystallization temperature was not affected by the use of a ligand, but the refractive index of the films prepared with a ligand was lower than that of the films without one. The presence of a ligand is shown to be useful in controlling the optical properties of TiO2-SiO2 films.