A rare ketohexose, L-psicose, was produced from allitol by Gluconobacter frateuril IFO 3254. The transformation reaction was carried out at 30 degrees C with shaking using the washed cells. The conversion rate was about 98% when 10% allitol was used. The cells grown on tryptic soy broth containing 1% glycerol were found to have the best conversion potential. Cells stored at -20 degrees C for 10 d showed almost the same transformation activity as intact cells.