The oxidation behavior of Hf-Al-C ceramics containing 37.5 wt% Hf(3)Al(3)C(5), 30.5 wt% Hf(2)Al(4)C(5), and 32.0 wt% Hf(3)Al(4)C(6) has been investigated at 900 degrees-1300 degrees C in air. The oxidation kinetics approximately follows a linear law with the activation energy of 194 +/- 12 kJ/mol. The oxidation resistance of Hf-Al-C ceramics at high temperature is superior to HfC. The oxide scale is porous and composed of well-mixed t-HfO(2) and Al(2)O(3) as well as residual free carbon. The stabilization mechanisms of t-HfO(2) and free carbon have been discussed. The simultaneous oxidation of Hf and Al in Hf-Al-C ceramics can be attributed to their close oxygen affinity as well as the strong coupling between Hf-C blocks and Al-C units in the crystal structures.