A catalyst including cobalt, zinc oxide and aluminium is described, having a total cobalt content of 15-75% by weight (on reduced catalyst), an aluminium content .gtoreq.10% by weight (based on ZnO) and which when reduced at 425.degree. C., has a cobalt surface area as measured by hydrogen chemisorption at 150.degree. C. of at least 20 m.sup.2/g cobalt. A method for preparing the catalyst is also described including combining a solution of cobalt, zinc and aluminium with an alkaline solution to effect co-precipitation of a cobalt-zinc-aluminium composition from the combined solutions, separating of the co-precipitated composition form the combined solutions, heating the composition to form an oxide composition, and optionally reducing at least a portion of the cobalt to cobalt metal. The catalysts may be used for hydrogenation reactions and for the Fischer-Tropsch synthesis of hydrocarbons.