Cobalt-based catalysts were prepared by precipitation method. This research investigated the effects of different supports cobalt loading, promoters, loading of promoters and calcination conditions on the catalytic performance of cobalt catalysts for Fisher-Tropsch synthesis (FTS). It was found that the catalyst containing 40 wt.% Co/TiO2 promoted with 6 wt.% Zn was an optimal catalyst for the conversion of synthesis gas to hydrocarbons especially light olefins. The activity and selectivity of optimal catalyst were studied in different operational conditions. The results showed that the best operational conditions were the H-2/CO reversible arrow 2/1 molar feed ratio at 240 degrees C and GHSV = 1100 h(-1) under atmospheric pressure. Characterization of catalysts were carried out by using X-ray diffraction (XRD), thermal gravimetric analysis (TGA), hydrogen temperature program reduction (H-2-TPR), N-2 physisorption measurements such as Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods. (C) 2011 Elsevier B.V. All rights reserved.