Isomerization of n-hexane into bi- and tri-branched products was studied at atmospheric pressure on NI-WOx/Al2O3-SiO2 catalysts. Two groups of catalysts (A and B) were prepared by using the sol-gel method. The objective of the present study is the selection of the catalyst having the best isomer (bi- and tri-branched) yield under optimum operating conditions (reaction temperature, reduction temperature, flow duration, etc.). The results show that the introduction of tungsten (group B) modifies siginificantly the catalyst activity and that the optimum nickel amount in these catalysts is 15 wt. %. When a steady flow is achieved (100 min), the catalyst containing 15 % nickel and 10 % tungsten exhibits the highest and largest selectivity at a reaction temperature of 250degreesC and a reduction temperature of 430degreesC.