The kinetics of dilute acid catalyzed hemicellulose hydrolysis in corn cob and sunflower seed hull was investigated with sulfuric acid concentrations of between 0.2 and 1 N at temperatures of 98-130 degrees C. Batch hydrolysis data for two different lignosellulosic biomasses were correlated with a general kinetic model which assumed that hemicellulose was composed of two fractions with each fraction reacting according to first-order rates. When the concept of fast- and slowly-hydrolyzing hemicellulose was combined with a first-order-rate model for xylose degradation a complete kinetic model was developed. The respective rate constants were determined as functions of temperature and sulfuric acid concentration by a non-linear regression analysis. The results indicated that the kinetic parameters involved in hydrolysis reactions were dependent on substrate material. The experimental and model results were in a satisfactory agreement