C-type cubic (Y_1−xPr_x)₂O_3+δ (0 ≤ x ≤ 0.20) catalysts were prepared for direct NO decomposition. The highest catalytic activity was exhibited by (Y_0.90Pr_0.10)₂O_3+δ, with a N₂ yield of 79% at 900 °C. This catalyst also sustained a high level of NO conversion even in the presence of O₂ or CO₂.