Sugar cane bagasse was hydrolysed using nitric acid at variable concentration (2-6%), reaction time (0-300 min) and temperature (100-128 degreesC). The concentration of sugars released (xylose, glucose and arabinose) and degradation products (acetic acid and furfural) were determined and the kinetic parameters of mathematical models for predicting them in the hydrolysates were obtained. The influence of temperature was also studied using the Arrhenius equation. Applying the kinetic models obtained, the optimal conditions selected were: 122 degreesC, 6%, HNO3 and 9.3 min. Using these conditions, 18.6 g xylose/l; 2.04 g arabinose/l; 2.87 g glucose/1; 0.9 g acetic acid/l and 1.32 g furfural/l were obtained. Comparison of these results with those obtained using sulphuric and hydrochloric acids demonstrated that the nitric acid was the most efficient catalyst for hydrolysis. (C) 2003 Elsevier Ltd. All rights reserved.