Carbon-supported nickel-molybdenum sulfide (NMC) was prepared using an active carbon with a surface area of 3070 m(2)/g for the slurry-phase hydrocracking of petroleum residue. The hydrocracking catalysis was evaluated, in comparison with that for an alumina-supported nickel-molybdenum sulfide (NMA). The experimental hydrocracking was performed with the atmospheric residue of the Middle Eastern crude at 350-450 C for 2 h in an autoclave initially pressurized with 5 MPa of hydrogen. NMC was more active in the radical quench reaction with the thermally decomposed residue than NMA, which was effective in reducing the residual fraction. NMC also provided less sulfur content for the liquid product than NMA. For the carbon-supported catalyst, it was evident that an increase in the surface area of the support caused enhancement of the hydrocracking catalysis. These results were verified through a reaction of the model compounds, 1-methylnaphthalene and dibenzothiophene. The higher activity was due to the better dispersion of the active component on the supporting material. The catalytic C-C bond scission was the minor reaction over any of the catalyst samples. Deterioration of NMC was measured through the experimental hydrocracking series that recycled the catalyst. In addition, the carbon deposit was discussed in relation to the adsorption of the residual fraction on the catalyst.