The effect of thermal aging on the combustion kinetics of coke deposited on a commercial Cr2O3-Al2O3 catalyst has been studied. Catalyst aging was produced in several operation and regeneration cycles involving high temperatures and the alternate use of reducing or steam-containing oxidizing atmospheres. As a consequence of aging, the intrinsic regeneration constant decreased, while the activation energy remained unchanged compared with that of the fresh catalyst. This indicates that the regeneration mechanism is not modified, and the effect of catalyst aging is to reduce the number of active regeneration sites on the surface through a partial sintering process.