A study was made of the kinetics of the oxidation of carbon monoxide to form carbon dioxide. The catalyst was high purity zinc oxide. A liquid nitrogen trap was used to remove the product carbon dioxide, thereby virtually eliminating any poisoning effect of CO2 on the reaction. A natural convection loop provided the means for circulating gases past the catalyst and the nitrogen trap in the batch system. Pressure change due to reaction was the criterion used to determine the kinetics. The reactions were studied between 250°C and 310°C, with initial total pressure of approximately 35 torr. The overall order dependency was found to be approximately 1.1, with individual orders of approximately 0.9 and 0.2 for carbon monoxide and oxygen, respectively. The apparent activation energy for the reaction was found to be 15.1 Kcal/mole.