Study was made of the catalytic activity and selectivity of alumina and silica supported palladium and ruthenium catalysts in cinnamaldehyde hydrogenation. Palladium and ruthenium beta-diketonate complexes were introduced onto alumina and silica supports by atomic layer epitaxy (ALE) and by conventional impregnation technique. Palladium catalysts were more active than ruthenium catalysts. ALE-prepared palladium catalysts showed the highest initial activity because of the small metal particle size. However, the reactivity of surface palladium atoms was highest in the large metal particles. ALE-prepared Ru on silica showed good selectivity in cinnamaldehyde hydrogenation; only hydrocinnamaldehyde and 3-phenyl-1-propanol were formed. All other catalysts gave a variety of products. ALE-prepared Ru on alumina had the highest selectivity to cinnamyl alcohol.