Seventeen cultures belonging to three genera of facultative bacteria (Serratia, Cellulomonas, and Corynebacterium) were screened for the production of xylitol, a sugar alcohol used as a sweetener in the pharmaceutical and food industries. The bacterial strains that utilized D-xylose for growth were investigated for xylitol production. A chromogenic assay of both solid and liquid cultures showed that ten of the 17 bacteria screened could grow on D-xylose and produce detectable quantities of xylitol during 24-96 h of fermentation. Among the screened cultures, Corynebacterium sp. B-4247 produced the highest amount of xylitol. In addition, the ten bacterial cultures that initially produced xylitol were studied for the effect of the environmental factors, such as temperature, concentration of D-xylose and aeration, on xylitol production.