Sugarcane bagasse is generated approximately 4 million tons per year as an agricultural residue in Thailand. It can be considered as an important lignocellulosic resource. Lignocelluloses are composed of three main components such as cellulose, hemicelluloses and lignin. Cellulose and hemicelluloses are present in polysaccharide form. These polysaccharides can be converted to fermentable sugars and used as alternative raw materials for ethanol production. They can be also converted to various valuable chemicals. In contrast to starch and sugars, liquefaction of these cell wall polysaccharides is, however, far more difficult due to its native structure of lignocellulosic materials and the presence of lignin. In addition, hydrolysis of cellulose and hemicelluloses could not be optimized at the same treatment severity. Cellulose demands a treatment of higher severity to be completely hydrolyzed than amorphous hemicelluloses because of its crystallinity. Therefore, the objective of this project is to study a two-step hydrolysis process for saccharides production from sugarcane bagasse with diluted sulfuric acid, with the first stage to selectively hydrolyze hemicelluloses and the second stage for cellulose. The effect of treatment temperatures and times on the hydrolysis of hemicelluloses and cellulose was examined by using 3wt% sulfuric acid solution in a 10-ml batch reactor. In the first stage, sugarcane bagasse was hydrolyzed at 90-150oC for 0-60 minute. The hydrolyzates and solid residues from the first stage treatment were collected and studied their chemical compositions. The most appropriate hydrolysis condition was considered based on the total reducing sugar yields. On the other hand, the solid residue obtained from the first stage at the appropriate condition was used for the second-stage hydrolysis at 170-210oC for 0-60 minute to find the appropriate temperature and time. It was found that hemicelluloses were mainly hydrolyzed under the first-stage experiment conditions. Xylose and xylo-saccharides were recovered as the major hydrolyzed products. Significant hydrolysis of cellulose and production of glucose and cello-saccharides were observed in the second stage. Decomposed compounds such as furfural and 5-hydroxymethylfurfural (5-HMF) from the dehydration reaction of mono-saccharides were also detected. Based on the obtained results, the most appropriate hydrolysis temperature and time in the first stage treatment were at 130oC and 60 minute, respectively, and those of the second stage were 170oC and 60 minute. These lines of study provide very useful information to utilize efficiently lignocelluloses for biochemicals and biofuels.