The effect of sandblasting and heat treatment on biaxial flexure strengths of the zirconia/alumina nanocomposite stabilized with cerium oxide (Ce-TZP/Al2O3 nanocomposite) was evaluated in comparison to that of yttria stabilized tetragonal zirconia polycrystals (Y-TZP). The disc-shaped specimens of the nanocomposite and Y-TZP were sandblasted with 70)m alumina powder. After sandblasting, half of the specimens were heated at 1000°C for 5 min. The biaxial flexure strengths of Y-TZP were independent on the sandblasting, but decreased with the heat treatment. On the other hand, the biaxial flexure strength of the nanocomposite increased with the sandblasting and significantly decreased with the heat treatment. The content of monoclinic ZrO2 of Y-TZP and the nanocomposite increased with the sandblasting pressure and dramatically decreased with the heat treatment. These results suggest that the stress-induced transformation from tetragonal to monoclinic of the nanocomposite occurs more easily than Y-TZP.