The effect of a small amount of Sb doping (5%) on the formation of the high temperature superconducting phase has been investigated on the Bi 1.5 Pb 0.5 Sr 2 Ca 2 Cu 3 Oy compound. It is observed that at 860 • C the Tc zero (T 0 c ) value depends on the sintering time. It first increases to a maximum value of 96 K and then decreases to a stable lowest value of 88 K. The samples have been characterized by X-ray diffraction (XRD), four probe electrical resistance and current density measurements. The XRD revealed the presence of two phases: an orthorhombic high-Tc 2223 phases with lattice constants a = 5.395Å, b = 5.508Å, c = 37.0422Å and another tetragonal low-Tc 2212 phase with lattice constants a = b = 5.419Å, c = 30.832Å.