Inoculation of kimchi, a Korean style fermented Chinese cabbage, with Propionibacterium freudenreichii ss. shermanii (ATCC No. 13673) increased vitamin B12 production to a maximum of 102 ng/100g from 47 ng/100g in the control at 1 wk of fermentation at 4°C. Soy flour (0.5%) or beef extract (0.05%), added as protein sources to the inoculated kimchi, further increased the vitamin activity to 197 and 203 ng/100g, respectively, at 1 wk. The fresh, unfermented kimchi contained 16.8 mg of ascorbic acid per 100g and the vitamin decreased at a constant rate during the first 5 wk of fermentation.