Iron silicalite samples with a different degree of crystallinity have been synthesized and characterized. Reduced samples were then tested as catalysts for carbon dioxide hydrogenation. It is observed that whenever the zeolitic phase is present, reduction of the iron species is strongly encumbered. As a consequence, over such catalysts the reverse water-gas shift reaction occurs specifically while formation of hydrocarbons does not occur. This is attributed to the lack of formation of surface carbidic species which appear to be responsible for the hydrocarbon formation.