Several methods have been proposed to improve the conversion of catalytic oxidation reactions. Gases with low enthalpy contents or gases that contain small amounts of combustible compounds can be converted much move efficiently in a reactor with reciprocating flow. The solid phase exhibits an inertia behavior insofar as it does not reach equilibrium with the gas temperature at the reactor ends. The solid-phase temperature at the center of the bed is considerably higher than in the unidirectional case. Results for the oxidation of CO at different inlet gas temperatures and switching periods are presented. An optimum period is found at which maximum conversion occurs. An estimate of the maximum temperature in the reactor is derived.