Microwave dielectric properties and far-infrared reflectivity spectra of the (1 - y)CaTiO3-yLi(1/2)Sm(1/2)TiO(3) ceramics were investigated in the range of 0.0 less than or equal to y less than or equal to 1.0. The dielectric constant, unloaded Q value, and temperature coefficients of the resonant frequency (TCF) of the specimens decreased with increasing Li1/2Sm1/2TiO3. At y = 0.7, a nearly zero TCF value was obtained, with a high dielectric constant (K = 114) and an unloaded Q (Q.f = 3700). Based on analysis of the far-infrared reflectivity spectra from the 50 to 4000 cm(-1) range, which were evaluated using Kramers-Kronig analysis and the cm classical oscillator model, the change in the Q.f value and dielectric constant of the specimens could be explained by intrinsic factors such as ionic polarization and dielectric loss (tan delta(j)). The relative tendency of calculated dielectric constant and Q f values agreed well with that of the measured values.