In this study, Gd2O3, Nb2O5, Sc2O3, ZrO2, and BaO are chosen as co-dopants with Y2O3 to stabilize delta phase Bi2O3 ceramics. Under a fixed dopant concentration, the effects of the co-dopants on the phase stability and electrical properties of Bi0.76Y0.24-xMxO1.5+delta (M = Gd, Nb, Sc, Zr, and Ba) are investigated. Based on the study results, all co-doped specimens exhibit a sintering temperature lower than that of the Bi0.76Y0.24O1.5 ceramic. The Bi0.76Y0.24-xGdxO1.5, Bi0.76Y0.24-xNbxO1.5+delta, and Bi0.76Y0.24-xScxO1.5 ceramics retain a cubic fluorite structure of 8-Bi203 phase while Bi0.76Y0.24-xBaxO1.5-delta displays a mixture of cubic and rhombohedral phases. Despite the fact that the ionic radius of Sc3+ and Zr4+ ions are smaller than that of Y3+ ion, the lattice constant of the Bi0.76Y0.24O1.5 ceramic rises with the Gd2O3, Sc2O3, or ZrO2 replacement but drops with the Nb2O5 substitution. Of the compositions studied, the Bi0.76Y0.20Zr0.04O1.5+delta ceramic emerges with the best electrical conductivities of 0.27 and 0.55 5cm(-1) at 600 and 700 degrees C, much higher than those of the Y2O3-doped and ZrO2-doped Bi2O3 ceramics. It is observed that, with the same total dopant concentration, the co-dopant stabilized Bi2O3 ceramics outperforms their single-dopant stabilized counterparts in terms of conductivity, probably due to the larger lattice constants. (C) 2012 Elsevier B.V. All rights reserved.