Polycrystalline samples of Ti3SiC2 were oxidized in air in the 900 to 1400 degrees C temperature range. The oxidation was parabolic with parabolic rate constants, k(p), that increased from 1 x 10(-9) to 1 x 10(-4) kg(2) m(-4) s(-1) as the temperature increased from 900 to 1400 degrees C, respectively which yielded an activation energy of 370 +/- 20 kJ/mol. The scale that forms was dense. adhesive. resistant to thermal cyclings and layered. The outer layer was pure TiO2 (rutile), and the inner lager consisted of mixture of SiO2 and TiO2. The results are consistent with a model in which growth of the oxide layer occurs by the inward diffusion of oxygen ana the simultaneous outward diffusion of titanium and carbon. The presence of small volume fractions (approximate to 2%) of TiCx in Ti3SiC2 were found to have a deleterious effect on the oxidation kinetics.