Using the X-ray diffraction, internal friction, 4-point bending, and electron microscopy methods we have studied the structural compatibility and influence of Y2O3 and HfO2 dopants addition on the structure and phase composition of ZrO2 powders and ceramics based on them. The mechanical properties of ZrO2–Y2O3-HfO2 (YSZ) system have been investigated.It was determined that the similarity of the structure and properties of yttrium and hafnium oxides is not complete. The individual structural features of ZrO2, Y2O3, and HfO2 oxides reviled themselves during the formation of ternary systems of the YSZ-Hf type. Studies of the nY2O3–ZrO2 - mHf2O3 system in the range of hafnium amount from 1 to 15 wt% and yttrium oxide concentration from 0 to 12 mol% showed the possibility of increase in the values of physical and mechanical properties of common two-component zirconium ceramics by the forming ternary systems of the YSZ-Hf type.