Eucalyptus globulus wood samples were treated at 120 or 130 degrees C with 95% acetic acid solutions containing 0.2 or 0.4% HCl. At given reaction times, the composition of both solid residues and liquors were determined. For the various experimental conditions assayed, the time courses of unconverted hemicelluloses, sugar concentrations and furfural concentrations were measured. These variables were correlated with the reaction rime following equations derived from a kinetic model, and this provided a satisfactory interpretation of the experimental results. The set of kinetic parameters calculated by regression of experimental data provided information useful for simulation and design purposes.