Using the hot pressing method, the Ti3SiC2 materials having fine and coarse grains were synthesized from TiC0.6 and Si powders, and the Ti(3)AIC(2) materials having fine and coarse grains were also synthesized from TiC0.6 and Al powders. The cyclic oxidation between 900 and 1200 degrees C for 40 hr in air resulted in the formation of an outer Tio(2) layer and an inner (TiO2+ amorphous SiO2) mixed layer for Ti3SiC2, and the formation of an outer TiO2 layer and an inner (Tio(2)+ Al2O3) mixed layer for Ti(3)AIC(2). The effect of the grain size on the cyclic oxidation resistance was not significant.