Abstract: The aim of this study is to investigate phase equilibria in the ZrO2-Nd2O3-Y2O3 System in the temperature range 1250-1600°C for the Nd2O3 rich compositions and to study transformations of three phase assemblage consisting of the Nd2O3 hexagonal phase A, monoclinic phase B and pyrochlore under increasing temperature. The samples were characterized by means of X-Ray Diffraction (XRD), Scanning Electron Microscopy with Energy Dispersive X-ray analysis (SEM/EDX) and Differential Thermal Analysis (DTA). The results of XRD show that at 1250 and 1400°C the equilibrium phases are B+Pyr and probably Nd2O3-A is also present in small amount (~1%). At 1600°C equilibrium phases are Flu+Nd2O3-A. Therefore, two phase transformations occur in the range 1400-1600°C. DTA experiment was performed in range 25-1700°C and two phase transformations have been found: Pyr →Flu at ~1471°C and B→A at ~1608°C. This was confirmed by XRD and SEM/EDX.