Characterization (BET and TPD) and reaction studies were conducted with activated carbon supported iron catalysts (Fe/AC) used for the Fischer-Tropsch synthesis (FTS). The TPD study showed that there existed interactions between metals and the AC surface. Greater association of Cu and K promoters with the AC surface resulted in stronger promoter to surface interaction, which enhanced the H-2 desorption ability of the Cu and K promoted Fe/AC catalyst prepared under vacuum impregnation (VI). Catalytic behavior of a Fe/AC catalyst (VI-15 Fe/2 Cu/2 K/81 AC, in parts per weight) was studied in a 1-liter slurry phase continuous stirred tank reactor. The catalyst presented moderate syngas conversion (44.3-60.6%) and high gaseous selectivity (CH4, 12.8-15.1% and C-2-C-4, 42.4-46.1%) under 304degreesC, 3.0 MPa, 1.1 L(STP)/g-cat/h, and H-2/CO = 2.0 during 166 h of testing. Detectable hydrocarbons up to C-18 were formed on the Fe/AC catalyst.