Hydrolysis of the hemicellulosic fraction of sugarcane bagasse by sulphuric acid was performed in laboratory (25 mL) and semi-pilot (25 L) reactors under different conditions of temperature, time and acid concentration. On the laboratory scale, the three highest recovery yields were obtained at: 140ºC for 10 min with 100 mgacid/gdm (yield=73.4%); 140ºC for 20 min with 100 mgacid/gdm (yield=73.9%) and 150ºC for 20 min with 70 mgacid/gdm (yield=71.8%). These conditions were also used for hydrolysis in a semi-pilot reactor, and the highest xylose recovery yield (83.3%) was obtained at 140ºC for 20 min with 100 mgacid/gd