The dehydrogenation catalyst consisting of 50 to 95% by weight of an iron compound and 5 to 50% by weight of at least one promoter and/or at least one stabiliser is prepared by using goethite and/or haematite having a specific surface area of 1 to 50 m<2>/g, measured by BET, as the iron compound and is mixed or kneaded with the further component or components and then moulded. The catalyst is used for the dehydrogenation of ethylbenzene to styrene.