The effect of both the Cr/Zn atomic ratio of the Cr2O3-ZnO catalyst and the Si/Al ratio (different surface acidity) of the ZSM-5 catalyst on the activity and selectivity to gasoline is studied, when a physical mixture of both catalysts is used for transformation of syngas into gasoline in a single step. Furthermore, the composition of each catalyst required for a good compromise between activity and selectivity and for a high aromatic content in the gasoline has been determined. The kinetic behavior of these catalysts has been compared with that of others which have been prepared by combining conventional metallic catalysts in methanol synthesis with a ZSM-5 catalyst.