Abstract—: (1 – x)Ba(Ti0.75Sn0.25)O3 ∙ xPbTiO3 (0 ≤ x ≤ 1) samples prepared by a standard ceramic processing route have been characterized by X-ray diffraction, thermogravimetry, and dielectric, piezoelectric, and pyroelectric measurements. The results demonstrate that the system in question contains solid solutions with the perovskite structure, which have cubic symmetry for x < 0.2 and tetragonal symmetry for x ≥ 0.2. Increasing the percentage of PbTiO3 in the samples has been shown to cause sequential changes in their dielectric properties in the following sequence: ferroelectric relaxor, reentrant ferroelectric relaxor, ferroelectric with a diffuse phase transition, and conventional ferroelectric. © 2020, Pleiades Publishing, Ltd.