(Yb1-xPrx)(2)O3+delta catalysts with C-type cubic structure were synthesized by a co-precipitation method. By introducing the Pr ion into Yb2O3, the enhancement in the catalytic N2O decomposition activity was recognized through the improvement of the redox behavior due to the synergistic effects of Yb2+/3+ and Pr3+/4+ ions without any noble metal contribution. Among the samples prepared, (Yb0.85Pr0.15)(2)O3+delta exhibited the highest N2O decomposition activity, and can completely decompose N2O at 600 degrees C.