In order to produce xylitol from hemicellulose hydrolysate which is widely used as a substrate, the development of strain such as catabolite derepressed mutant is required. After treatment of Candida sp. with EMS, GM-17 and PM-34 as catabolite derepressed mutant were isolated from Candida guilliermondii and Candida parapsilosis, respectively. Mutant GM-17 and PM-34 simultaneously assimilated xylose and glucose during the fermentation. The specific xylose reductase and xylitol dehydrogenase activities of mutant strains were also higher than those of wild strains in glucose medium and mixed medium of glucose and xylose. The xylitol productivity and yield of mutant GM-17 and PM-34 were improved as compared to the wild types in the mixed medium. The xylitol productivity and yield of mutant GM-17 were 0.09 g/L·hr and 0.56 g-xylitol/g-xylose, and those of mutant PM-34 were 0.21 g/L·hr and 0.52 g-xylitol/g-xylose in the mixed medium, respectively.