A highly active catalyst for the skeletal isomerization of butane to isobutane was obtained by mechanically mixing S0(4)/ZrO2 and Ru/SnO2; Ru/SnO2 was prepared by impregnating tin hydroxide with a solution of RuCl3 followed by calcining at 450 degreesC (0.5 wt.% Ru). The catalyst was much more active than Ru-SO4/ZrO2 prepared by co-impregnation of zirconia with the Ru and sulfate materials the temperature difference to show the same conversion between both catalysts being 57 degreesC. The effect of mixing of Ru was observed with other metal oxides as supports, Fe2O3, Al2O3, ZrO2, TiO2, and SiO2; the calcination temperature of the Ru-impregnated hydroxides was 250, 300, and 400 degreesC for the latter three, respectively.