Alumina and silica-alumina supported Ru-Pt catalysts were evaluated for the ring opening of naphthenes. Pt, Ru and Ru-Pt catalysts were prepared by impregnation of inorganic precursors over γ-alumina and silica-alumina supports. The catalysts were evaluated by temperature programmed reduction (TPR), pyridine temperature programmed desorption (TPD), CO-FTIR and by test reactions of 33DM1B isomerization, cyclohexane dehydrogenation, cyclopentane hydrogenolysis and ring opening of decalin. The strong interaction between the metals (Pt-Ru) was attributed to their reduction occurring simultaneously. The acidity and strength of the acid sites of the monometallic Ru catalyst were higher than those of the monometallic Pt catalyst. Total acidity (Lewis and Brønsted) and strength of the acid sites were higher for the silica-alumina supported catalysts. The silica-alumina catalysts had ten times more Brønsted acidity than the γ-alumina ones and an increased activity and selectivity to decalin ring opening products. Supported monometallic Ru had the best performance for the ring opening reaction.