Wheat straw, a lignocellulosic waste material, can be used as a raw material for the production of high-value products such as xylose for xylitol production or phenolic compounds that have antioxidant activity. There is a growing interest in the use of lignocellulosic wastes for conversion into various chemicals because of their low cost and the fact that they are renewable and abundant. The objective of this study was to determine the effects of H2SO4 concentration, temperature and reaction time on the production of sugars (xylose) and phenolic compounds. Response surface methodology (RSM) was used to optimize the hydrolysis process to obtain high xylose yield and phenolic compounds. The optimum reaction temperature, reaction time and acid concentration were 120 degrees C, 45 min and 4.7% respectively. Under these conditions, xylose and phenolic of the hydrolysate was found to be 0.16 g/g-wheat straw and 0.014 g-gallic acid/g-wheat straw, respectively. (C) 2012 Elsevier B.V. All rights reserved.