AbstractA series of Ba_1-x-ySr_xCa_yTiO₃ compounds were prepared with varying average ionic radii and cation disorder on A-site. All samples showed typical ferroelectric behavior. A simple empirical equation correlated Curie temperature, T_C, with the values of ionic radii of A-site cations. This correlation was related to the distortion of TiO₆ octahedra observed during neutron diffraction studies. The equation was used for the selection of compounds with predetermined values of T_C. The effects of A-site ionic radii on the temperatures of phase transitions in Ba_1-x-ySr_xCa_yTiO₃ were discussed.