In this study, after doping Lu2O3 to -Bi2O3 in the range of 11% n 20% in a series of different mole ratios, heat treatment was performed by applying a cascade temperature rise in the range of 700-800 degrees C for 72 hours and new phases were obtained in the (Bi2o3)1-x(Lu2o3)x system. After 72 hours of heat treatment at 800 degrees C, mixtures containing 14-16% Lu2O3 formed a face-centered cubic phase. Mixtures containing 11- 13%, 17%, 18% mole Lu2O3 were subjected to a quenching process at 825 degrees C and face-centered cubic phases were obtained. With the help of XRD, the crystal systems and lattice parameters of the solid solutions were obtained and their characterization was carried out. Thermal measurements were made by using a simultaneous DTA/TG system. The total conductivity (sigma T) in the -Bi2O3 doped with Lu2O3 system was measured using the four-probe DC method. Keywords: Bismuth oxide; lutesium oxide; oxygen ionic conductivity; X-ray techniques; thermal analysis.