The experimental procedure for investigation of the Fischer-Tropsch reaction in a stirring tank slurry reactor and the analytical methods for quantitative identification of the products were described. The results of the 760-hour stability test of commercial Ruhrchemie catalyst (100Fe/4.3Cu/4.1K/25SiO2) in n-octacosane (C28H58) were presented. The effect of activation procedure on catalyst activity and stability was discussed.