Xylitol production from sugarcane bagasse hemicellulosic hydrolyzate was evaluated in a fluidized bed reactor operated in semi-continuous mode, using cells immobilized on porous glass. The fermentative process was performed during five successive cycles of 72 h each one. The lowest xylitol production occurred in the first cycle, where a high cell concentration (12 g l−1) was observed. In the subsequent cycles the xylitol concentration was ever increasing due to the cells adaptation to the medium. In the last one, 18 g xylitol l−1 was obtained with a yield factor of 0.44 g g−1 and volumetric productivity of 0.32 g l−1 h−1.