We have found that Zr- and Li-modified Ru/SiO2 catalysts (Q-15) are extremely stable and can be used in FT synthesis to maintain the conversion rate of CO constant even after 33 h. Modification of Ru/SiO2 by Zr (5 wt%) and Li (0.1 wt%) resulted in a remarkable increase in the stability of the catalyst. Taking into account surface acidity and reducibility, we assumed that this remarkable stability is due to the cooperative effects of Ru, Zr, Li, and the SiO2 support.