Superconductivity has been established in oxide materials, containing Bi, Cd, Sr, Ca and Cu. Samples with zero resistance of about 100 K have been synthesized, with nominal compositions Bi4Cd1Sr3Ca3Cu4Oy, Bi2Cd1Sr2Ca3Cu3Oy and Bi2Cd1Sr2Ca2Cu3Oy. On the basis of X-ray diffraction and differential thermal analyses results provide sufficient reasons to suppose the existence of a new, still unidentified phase, in which Cd probably participates. This phase probably promotes the superconductivity in the BiCdSrCaCuO system. © 1990.