Low and moderate loading (1-15%) Co/alumina catalysts prepared by aqueous impregnation have been previously studied using temperature-programmed desorption(TPD) and temperature-programmed surface reaction(TPSR). These catalysts are characterized by their relatively low percentages of reduction and high dispersions at low loadings or low dispersions and high degrees at moderately high metal loadings. The physical properties and Fischer-Tropsch activities of these new catalyst have been reported but their behavior has not been characterized by TPD or TPSR prior to this study. This report will focus on effects observed in CO TPD and TPSR of H2 with adsorbed CO caused by variations in the extent of reduction, alumina dehydroxylation, metal loading, and pretreatment of these catalysts. TPD data will be presented which indicate that metal loading, extent of reductin, and the state of dehydroxylation on cobalt metal crystallites.