The temperature-dependent phase transitions of Bi0.95þdFe0.9Zr0.1O3 have been studied using hightemperature x-ray powder diffraction together with differential scanning calorimetry measurements. The results show that Bi0.95þdFe0.9Zr0.1O3 undergoes two phase transitions at 815 C and 905 C before decomposition at 920 C. It appears that Zr-doping seems to stabilize the high temperature phases in such compound. Both the sharp contraction in the unit-cell volume and enthalpy thermal hysteresis demonstrate that the ferroelectric phase transition (a/!b) at 815 C is of first order nature. In contrast, the highest b/!c phase transition at 905 C appears to be a second-order-like one. The analysis of the diffraction pattern in addition to Rietveld refinement strongly suggests a cubic symmetry for c-phase.