Composite materials containing Raney Ni and Cu-ZSM-5 are highly active catalysts for the selective catalytic reduction (SCR) of NO by NH3. Their catalytic properties were studied with particular attention to the influence of moisture and SO2 in the feed, and to effects of catalyst shaping operations. Composite materials (16-20 wt-% zeolite) were prepared by mixing the components, with different degree of segregation in the resulting pressed particles, or by growing ZSM-5 crystallites on the surface of leached Raney Ni, which were then exchanged with Cu ions. Catalytic tests were performed with 1000 ppm NO, 1000 ppm NH3, 2 % O-2 in He, at 3-6.5 10(5) h(-1) (related to zeolite component). With physical mixtures, the catalytic behaviour strongly depended on the mixing strategy, particles containing both Ni and zeolite being inferior to mixed Ni-only and zeolite-only particles. The SCR activity was promoted by 2 % H2O in the feed, SO2 (200 ppm) was a moderate poison at low temperatures, but indifferent or slightly promoting at high temperatures. A catalyst prepared from ZSM-5 grown on Raney Ni, which was ranked intermediate in dry feed, was promoted to excellent performance in H2O and SO2 containing feed at T > 700 K and was stable for 38 h at 845 K. The results suggest that SCR catalysts containing highly active zeolites should be produced avoiding shaping operations e.g. by use of zeolite crystallites grown on wire packings.