Fischer-Tropsch (FT) reaction involves conversion of syngas (a mixture of carbon monoxide and hydrogen) into higher hydrocarbons in the presence of an active catalyst. The syngas can be derived from non-petroleum feedstocks such as coal, biomass and natural gas, thus the FT reaction provides an alternative route for production of clean fuels. The FT process has received growing interest in recent years due to uncertainty in the Middle East, fast depletion of fossil fuel and environmental concern. This paper reports the synthesis, physicochemical properties and catalytic performance of cobalt-based catalyst in the FT reaction. The catalysts comprised metal nanoparticles supported on carbon nanotubes (CNTs) which were synthesized via a wet impregnation method. The catalysts were characterized using transmission electron microscopy (TEM), temperature-programmed reduction/desorption (TPR/TPD) and X-ray photoelectron spectroscopy (XPS). The performance of the cobalt-based catalyts in a FT reaction was evaluated in a fixed bed microreactor equipped with an on-line gas chromatograph for analyses of hydrocarbon products. The catalysts investigated in this work were Co/CNTs, 70Co30Mn/CNTs, 0.06%K/70Co30Fe/CNTs and 0.04%Nb/70Co30Fe/CNTs. TEM analyses revealed that the average sizes of the metal nanoparticles were 4-5 nm. Based on TPD analyses, the dispersion of these nanoparticles on CNTs were greater than 90%. The presence of both Co 2+ and Co 3+ ions were confirmed by XPS analysis. The 0.04%Nb/70Co30Fe/CNTs catalyst performed better than other catalysts in the FT reaction where it resulted in CO conversion of 35% and 16% C 5+ selectivity at pressure of 1 bar, 220 °C and H 2 :CO of 2:1. Using the same catalyst, the CO conversion and C 5+ selectivity increased to 60% and 57%, respectively when the pressure was increased to 20 bar.