Fischer-Tropsch synthesis (FTS) holds great potential for the production of clean transportation fuels, chemicals and other hydrocacbon products through the conversion of syngas (CO/H2) from abundant resources (coal, natural gas and biomass). Supported cobalt catalysts represent the optimal choice for the synthesis of long-chained hydrocarbons. However catalytic activity and selectivity are strongly affected by reaction conditions of the FTS process. Therefore, in this paper, study results on the effects of reaction conditions including of temperature, pressure, and space velocity on catalytic activity and selectivity of Co-K/gamma-Al2O3 for the FTS will be presented and discussed.