Bagasse conversion to H-2, CO and light gaseous hydrocarbons as gaseous fuels, and higher alcohols and ethers as liquid fuels and fuel additives were performed in a basic water medium with near-critical condition in presence of potassium promoted Cu/gamma-Al2O3-MgO catalysts. The catalysts were extensively characterized using ICP, XRD, TPR, BET, CO chemisorption and TEM techniques. In order to investigate support stability at reaction condition, XRD test also was carried out for used catalysts. Maximum dispersion of 48% and minimum average particles sizes of 8.4 nm were obtained for Cu20-K7.5/gamma-Al2O3-MgO catalyst. Copper and potassium effects on quality and quantity of gaseous and liquid products were investigated. The maximum amounts of H-2 (10 mmol g(-1) of bagasse) and total produced gases (41 mmol g(-1) of bagasse) were obtained with unpromoted Cu20/gamma-Al2O3-MgO catalyst. Addition of K increased the bagasse conversion to liquid fuels. Potassium made the process more selective for alcohols and ethers production. Maximum amount of alcohols and ethers (83.3 mmol g(-1) of bagasse) was obtained for Cu20-K7.5/gamma-Al2O3-MgO catalyst. (C) 2015 Elsevier Ltd. All rights reserved.