An investigation of the use of La- and Zn-promoters for Ru/SiO2 F-T catalysts has been carried out. It was found that, while the use of a La-promoter did not result in any improvement over the use of a K one, Zn-promotion resulted in much higher yields of olefins. The CH4 and olefin selectivities of the Zn-promoted Ru/SiO2 were essentially insensitive to temperature over the range 250-320 °C. The Zn-promoted catalyst was found to have many of the same catalytic properties previously found for Ru/ZnO, but was much more active. Thus, it is possible to achieve certain interesting catalytic properties for Ru by the use of Zn-promotion without having to make use of the low surface area support ZnO.