The direct synthesis of gasoline-range iso-paraffins from synthesis gas (CO + H-2, syngas) via modified Fischer-Tropsch (FT) reaction was investigated in the slurry phase reaction system, the contact state of hybrid catalyst components and the composition of hybrid catalyst were optimized in this reaction system. The results show that the FT reaction and the in situ hydroconversion of its products occurred over hybrid catalysts containing Co/SiO2, very high selectivity of gasoline-range iso-paraffins could be achieved. (c) 2007 Elsevier Ltd. All rights reserved.