Co-Si beta and Fe-Si beta catalysts prepared by a two-step post-synthesis method were characterised by EPR, diffuse reflectance UV-vis, XRD and N-2-physisorption. Iron and cobalt ions are present as isolated lattice tetrahedral Co-II and Fe-III species for low metal contents (0.7 and 0.9 wt.%, respectively). For higher iron content, FeOx oligomers appear. Zeolites with isolated Co-II and Fe-III species are active in selective catalytic reduction of NO with ethanol. On FeOx, oligomers the oxidation of NO to NO2 starts to dominate in the selective catalytic reduction of NO with ethanol at the temperatures higher than 700 K. (c) 2006 Elsevier B.V. All rights reserved.