L-Xylulose is an intermediate in certain metabolic pathways and is classified as a rare sugar. It shows important physiological effects such as acting as an inhibitor of alpha-glucosidase and decreasing blood glucose, and it can be employed to produce other significant rare sugars, such as L-ribose and L-xylose which contribute to the production of antiviral drugs. Chemical synthesis of L-xylulose was performed, but it is difficult and low yielding. The biotransformation from xylitol to L-xylulose by xylitol 4-dehydrogenase was studied intensively. This review describes the occurrence of L-xylulose in certain metabolic pathways, its bioproduction, and application potential.