D-Arabitol dehydrogenase (D-arabitol [Formula: see text]D-xylulose, D-arabitol:NAD oxidoreductase, EC 1.1.1.11) was found in the D-sorbitol-grown or D-mannitol-grown cells of Agrobacterium tumefaciens, Pseudomonas fluorescens, Pseudomonas aeruginosa, Pseudomonas coronafaciens, Sarcina aurantiaca, and Sarcina marginata. This enzyme was accompanied by D-sorbitol dehydrogenase. Activity of D-mannitol dehydrogenase (D-mannitol:NAD oxidoreductase, EC 1.1.1) was also found in Pseudomonas fluorescens, Pseudomonas coronafaciens, Pseudomonas aeruginosa, Sarcina marginata, and Sarcina aurantiaca. D-Mannitol dehydrogenase was produced from Lactobacillus brevis, L. pentoaceticus, L. gayonii, and Leuconostoc mesenteroides in fructose media. D-Fructose seemed to be essential for the enzyme production by L. brevis, but Leuconostoc mesenteroides produced an equal amount of the enzyme from D-glucose, D-fructose, or sucrose media. Mannitol was found to be effective for enzyme production in a shake culture of Leuconostoc mesenteroides and of L. brevis.