The oxidation and tensile properties of a Ni20Cr20Fe5Nb alloy and a Ni20Cr20Fe 5Nb1Y(2)O(3) alloy with nano-sized grains were compared with those of the comercial IN718 alloy. The oxidation resistance of the Ni20Cr20Fe5Nb1Y(2)O(3) alloy was superior to that of the Ni20Cr20Fe5Nb and IN 718 alloys. This superior oxidation resistance was the result of both the formation of dense oxides on the surface of the alloy and the interruption of Cr migration in the alloy by the addition of Y2O3. Moreover, the tensile property of the Ni20Cr20Fe5Nb1Y(2)O(3) alloy at room temperature and 400 degrees C was higher than that of the Ni20Cr20Fe5Nb and IN718 alloys by more than 300MPa (30%). This result can be attributed to the dispersion strengthening of Y2O3. The relatively low tensile strength at 600 degrees C and 800 degrees C of the alloys fabricated by mechanical alloying was attributed to grain refinement showing intergranular fracture at high temperatures.