The demand for renewable energy is increasing due to increasing energy consumption and global warming associated with increasing use of fossil fuels. Hydrogen gas is considered as a good energy carrier due to its high energy content. Biomass (e.g. agricultural and forestry residues, food industry wastes, and energy crops) is amenable to dark fermentative hydrogen production. However, lignocellulosic materials require pretreatment and/or hydrolysis prior to dark fermentation. This paper reviews potential biomass sources for hydrogen fermentation as well as the effects of different pretreatment and hydrolysis methods on sugar yields as well as hydrogen yields from hydrolyzates. The effects of process parameters on dark fermentative hydrogen production from lignocellulosic hydrolyzates are also discussed. (C) 2014 Elsevier Ltd. All rights reserved.