Using the enzymes glucose dehydrogenase (GDH) and hydrogenase, we have shown that a variety of sugars that are components of renewable resources can be enzymatically converted to molecular hydrogen. The rates at which hydrogen was evolved paralleled the substrate specificity of GDH. The highest rate of hydrogen production measured was 97.8 μmol/h, and the stoichiometric yield of hydrogen was 98% with 50 mM glucose as the substrate. Lactose, sucrose, cellulose, xylan, steam-exploded aspen wood, and starch also served as substrates for hydrogen production when the corresponding enzymes were included in the reaction mixture to generate the appropriate monosaccharide for which GDH has specificity. The data obtained are discussed in the context of the rate-limiting steps of hydrogen production from renewable sugar and the possible applications of enzymatic hydrogen production.