In the present work, samples of sugar cane bagasse were hydrolysed with phosphoric acid under mild conditions (H3PO4 2-6%, time 0-300 min and 122 degrees C) to study the feasibility of using the liquid phase as fermentation media. Solid yield, sugar concentrations and decomposition product concentrations were measured. The composition of hydrolysates, their purity and the ratio sugars/inhibitors were analyzed. Kinetic models were developed to describe the course of products of the acid hydrolysis. The course of xylose, glucose, arabinose, acetic acid and furfural were satisfactorily described by the models. The optimal conditions selected were 122 degrees C, 4% H3PO4 and 300 min. Using these conditions, 17.6 g of xylose/l; 2.6 g of arabinose/l; 3.0 g of glucose/l, 1.2 g furfural/l and 4.0 g acetic acid/l were obtained. The efficiency in these conditions was 4.46 g sugars/g inhibitors and the mass fraction of sugars in dissolved solids in liquid phase was superior to 55%. (c) 2005 Elsevier Ltd. All rights reserved.