A water slurry of cellulose was directly gasified into methane using reduced nickel on kieselguhr and sodium carbonate as catalysts at 400 degrees C under pressure (about 13 MPa) for 1 h. In the absence of the catalysts, cellulose at about 20 wt% was converted into the gas which consisted mainly of carbon dioxide. Cellulose at about 40 wt% was converted into a char-like-material (residue), and 40 wt% was lost due to the formation of water-promoted by the carbon balance (more than 90 %) and by the mole ratio (about 2) of hydrogen loss to oxygen loss. With increasing load of reduced nickel (from 0 to 20 wt% of the cellulose), the yield of residue and production of water decreased linearly (from 40 to 10 wt%) and gas yield increased linearly (from 20 to 80 wt%). The methane yield increased by the reduced nickel and mole ratio of CH4/CO2 approached unity with increasing load of reduced nickel. Reduced nickel would thus appear to catalyze the formation of methane and carbon dioxide through reaction of carbon and water. Sodium carbonate increased methane yield in the presence of reduced nickel, although the yield was negligible when sodium carbonate alone was added.