The purpose of this study was to investigate the supported catalyst of the type CuO-Al₂O₃ which has been described by Lockwood and Frazer (13). This type of catalyst is unique in that it has a high activity at low temperatures, is suitable for use at high temperatures and has been reported to be truly catalytic in the oxidation of carbon monoxide. Lockwood and Frazer (15) have described the preparation of a catalyst of this type. Their description of the method of preparation and of the quantities of materials used is rather inadequate for an exact duplication of the catalyst which they prepared and studied. The method of procedure used in the study of this catalyst has been to vary both the composition and heat treatment of the catalysts and to observe the subsequent change in catalytic activity. 1. Increasing the copper oxide content of the copper oxide-aluminum catalysts increases the activity of the catalysts at least over the composition range studied. 2. Increasing the temperature to which the copper oxide-aluminum oxide catalysts are heated increases the activity. 3. The temperatures required for the catalysts to exhibit 100% activity are all above 270°C. 4. It was found impossible to reproduce the copper oxide-aluminum catalyst which was prepared by Lockwood and Frazer. 5. A catalyst prepared from pure copper oxide was more active than any of the catalysts which were studied. / M.S.