The effect of addition of different amounts of MgO and Al 2O 3 to the starting composition of BPSCCO ceramic superconductor have been analysed by means of X-ray diffraction, magnetic measurements, SEM and EDS. The magnetic superconducting properties of BPSCCO are not directly influenced by the addition. The MgO seems to play just a passive role. The presence of Al 2O 3 induces, however, the formation of a new Al-rich paramagnetic phase which modifies the effective starting stoicheiometry increasing sample contamination by copper oxide and calcium cuprate.