A number of new catalytically active materials based on structured mesoporous zirconium dioxide modified with (NH4)(10)W12O41 and (NH4)(2)WO4 were prepared, and their activity in the n-butane hydroisomerization reaction in a flow reactor over the temperature range 300-400 degrees C was studied. The technique of WO, introduction into mesoporous zirconia was found to be important for the formation of the Pt/WOx/ZrO2 (.) ySiO(2) system.