Metal/cerium-oxide systems were practically not studied in hydrocarbon reactions. Chemisorption properties-in temperature programmed reduction, hydrogen adsorption, and H-2/O-3 titration-and catalytic behavior of ceria-supported Pt and Ph catalysts with different metal loadings and with two pre-reduction temperatures (LTR, T-R= 573 K and HTR, T-R= 773 K) were investigated. Pt/CeO2 was tested in transformation of n-hexane while Rh/CeO2 in ring opening of methylcyclopentane (MCP), Higher spillover activity was found for the LTR Ph samples than for HTR ones. The opposite was true for Pt. The Rh/ceria samples showed ordinary catalytic behavior: structure insensitivity was observed for the first C-C bond cleavage of MCP on Rh/ceria and the further reaction of the ring opening intermediates was affected by the surface hydrogen concentration. The Pt/LTR samples showed catalytic properties similar to EUROPT-1, while the HTR samples were different, namely the higher spillover activity caused high C-5-cyclization selectivity on the catalyst with low metal loading, and surprisingly high hydrogenolysis selectivity on that with higher metal loading.