Electrical conduction in bccγ-Bi2O3 doped with Sb2O3 was investigated by measuring electrical conductivity, as a function of temperature and oxygen partial pressure\(P_{{\text{0}}_2 } \), and ionic transference number. Theγ-Bi2O3 doped with 1 to 3 mol% Sb2O3 was stable up to 550° C and showed an oxygen ionic conduction in the\(P_{{\text{0}}_2 } \) region of 105 to 10−9 Pa. As the Sb2O3 content increased, ionic conductivity increased up to 2.5 mol % Sb2O3 (1.8×10−3Ω−1cm−1 at 500° C) and then decreased. However, the activation energy for ionic conduction remained almost unchanged. It was proposed that theγ-Bi2O3 contains a lot of oxygen vacancies and incorporated Sb5+ ions at tetrahedral sites which affect the concentration of oxygen vacancy effective for conduction.