Composites of beta -Ce2O3. 11Al(2)O(3) and tetragonal ZrO2 fabricated by a reductive atmosphere sintering of mixed powders of CeO2, ZrO2 (2 mol % Y2O3), and Al2O3. The composites had microstructures composed of elongated grains of beta -Ce2O3. 11Al(2)O(3) in a Y-TZP matrix. The beta -Ce2O3. 11Al(2)O(3) decomposed to alpha -Al2O3 and CeO2 by annealing at 1500 degreesC for 1 h in oxygen. The elongated single grain of beta -Ce2O3. 11Al(2)O(3) divided into several grains of alpha -AI(2)O(3) and ZrO2 doped with Y2O3 and CeO2. High-temperature bending strength of the oxygen-annealed alpha -Al2O3 composite was comparable to the beta -Ce2O3 . 11AI(2)O(3) composite before annealing.