Fischer-Tropsch Synthesis (FTS) was studied to produce C-5-C-12 hydrocarbons (gasoline range hydrocarbons) from syngas by using iron-cobalt catalysts supported on nanosilica. The nanosilica was produced by a simple and cheap method from haulm rice. Catalysts and precursors were characterized by X-ray diffraction (XRD), temperature programmed desorption and reduction (TPD and TPR), scanning electron microcopy (SEM), energy dispersive X-ray spectrometer (EDX), transmission electron microcopy (TEM), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and N-2 adsorption-desorption measurements. The effects of Co-Fe (based on support weight) wt%, Co/Fe molar ratios, calcination conditions and operational conditions on the catalytic performance were studied. It was found out that the catalyst containing Co-Fe/SiO2 = 11 wt% with Co/Fe = 3/1 had the best catalytic performance for production of C-5-C-12 hydrocarbons. The optimal operational conditions were H-2/CO = 2/1 molar feed ratio, T = 290 A degrees C, gas hourly space velocity (GHSV) = 1600 h(-1) and 12 bar total pressure. Additionally, the optimal catalyst was stable during 250 h without significant degradation in catalytic activity and its catalytic performance. [GRAPHICS] .