The effects of cellulose crystallinity, hemicellulose, and lignin on the enzymatic hydrolysis of Miscanthus sinensis to monosaccharides were investigated. A air-dried biomass was ground by ball-milling, and the powder was separated into four fractions by passage through a series of sieves with mesh sizes 250-355 microm, 150-250 microm, 63-150 microm, and <63 microm. Each fraction was hydrolyzed with commercially available cellulase and beta-glucosidase. The yield of monosaccharides increased as the crystallinity of the substrate decreased. The addition of xylanase increased the yield of both pentoses and glucose. Delignification by the sodium chlorite method improved the initial rate of hydrolysis by cellulolytic enzymes significantly, resulting in a higher yield of monosaccharides as compared with that for untreated samples. When delignified M. sinensis was hydrolyzed with cellulase, beta-glucosidase, and xylanase, hemicellulose was hydrolyzed completely into monosaccharides, and the conversion rate of glucan to glucose was 90.6%.