Gasification of sugarcane bagasse on activated-carbon- and titania-supported ruthenium (Ru/C and Ru/TiO2) catalysts in supercritical water was studied. Sugarcane bagasse was completely gasified to methane, carbon dioxide, and hydrogen over Ru/C and Ru/TiO2 catalysts at 673 K. The carbon yield of the gas products from sugarcane bagasse, cellulose, and lignin over the Ru/TiO2 catalyst at a water density of 0.33 g cm(-3) for 15 min was 50.3, 74.4, and 31.1 C %, respectively. In addition, it was observed that an increase in the water density enhanced the initial carbon yield of the gas products for 15 min. The recyclability of the Ru/C catalyst with complete gasification could make it a sustainable process.