The oxidation‐reduction kinetics of MnO in CO/CO2atmospheres at 1230°C were measured by gravimetric and electrical conductivity techniques. The dependence of the kinetics on time, inert gas dilution, total pressure, and specimen thickness indicates that the kinetics are controlled by a slow surface reaction step. Attempts to analyze the data quantitatively using equations for linear heat flow in a solid with a radiation boundary condition were unsuccessf