The effect of metal loading on structural properties and CO oxidation activity of coprecipitated Co/Al2O3 catalysts was investigated. The results indicated the participation of cobalt in the Co-Al skeleton for all coprecipitated samples. Environmental-SEM-EDXS studies showed that at loadings higher than ca. H, wt-%, cobalt formed layer-by-layer clusters on the surface; 16.8 wt.-% Co/Al2O3 displayed the highest activity and stability in CO oxidation.