In the present work, Fe-Co-Ce/Zeolite A-3 catalysts were prepared, using the impregnation method and applied in Fischer-Tropsch Synthesis (FTS). The catalyst's performance was investigated by changing the catalyst's composition and process conditions. Increased pressure from 2 to 10 and H-2/CO ratio from 1 to 4 were accompanied by decreased olefin to paraffin proportion and increased C4+ production. Decline in the GHSV led to decrease in methane and light olefin generation, and a significant increase in the number of carbon in the products. The catalysts were characterized by SEM, BET, STA and XRD. Catalyst composition was changed with different loading of support (Zeolite A-3) and metals (Fe, Co, Ce). Finally, 45%Fe-45%Co-10%Ce/60%Zeolite A-3 catalyst was judged to be the best composition to obtain the optimal operation conditions (high selectivity towards light olefins and low selectivity towards methane, simultaneously). [GRAPHICS] .