Microwave dielectric properties and far-infrared reflectivity spectra of the 0.3CaTiO(3)-0.7Li((1/2)-3+3x)Sm((1/2)+x)TiO(3) ceramics were investigated as a function of Sm substitution (0.0 less than or equal to x less than or equal to 0.12), The dielectric constant decreased as the Sm3+ substitution increased. The Q x f value increased, up to a solid-solution limit at x = 0.11, because of the change of vibration modes between the A-site cation and the TiO6 octahedron, and then decreased because of the formation of a secondary phase (Sm2Ti2O7). On the analysis of the far-infrared reflectivity spectra, in the 50-4000 cm(-1) range, the change of the dielectric loss and dielectric constant could be explained by the intrinsic factor.