Abstract: Layered perovskite-like oxides Bi_5–xCa_xFeTi₃O_15–δ with the structure of the four-layer Aurivillius phase were synthesized in the Bi₂O₃–CaO–TiO₂–Fe₂O₃ system by the solid-state reaction method. The features of the formation and thermal behavior of the solid solution synthesized were studied.