Three kinds of metal-loaded Y-type zeolites (nickel-loaded, palladium-loaded, and palladium- and nickel-coloaded Y-type zeolites) were examined as catalysts for hydrocracking of dibenzothiophene and 4,6-dimethyldibenzothiophene. The results indicated that palladium-and nickel-coloaded Y-type zeolite (Pd-Ni-Y) had very high activity for the above reaction under following conditions (at 320 degrees C for 1 h under an H-2 pressure in the presence of the above catalyst) : dibenzothiophene was completely converted to hydrocarbon gases (ethane, propane, and butane), mono-ring compounds (benzene and cyclohexane derivatives), and hydrogen sulfide. At slightly higher temperature or for longer reaction time compared with above reaction conditions, 4,6-dimethyldibenzothiophene was also hydrocracked to a higher extent. We also conducted characterization of these metal-loaded zeolites using X-ray photoelectron spectroscopy, NH3 temperature-programmed desorption, and FT/IR spectroscopy. These analyses indicated that Pd-Ni-Y has a large number of Bronsted acid sites. This might be one of the reasons for this high catalytic activity of Pd-Ni-Y.