The USP microbiological assay with L. leichmannii, ATCC 7830, was used to determine vitamin B12 activity in light rice miso, dark rice miso, barley miso, tempeh and tempeh burger. Unpasteurized misos were found to have the highest B12 content, averaging 0.21 μg/ 100g. Vitamin B12 activity in miso ranged from a high of 0.25 μg/ 100g in barley miso to a low of 0.15 μg/100g in light rice miso. Pasteurized tempeh contained 0.12 μg vitamin B12 per 100g food. Tempeh burger contained 0.06 to 0.11 μg vitamin B12 per 100g food. The variation in vitamin B12 activity found in these products may be due to different conditions used or produced during fermentation. Collaborative studies are needed and assessment of vitamin B12 pseudoform activity before these foods can be considered a source of vitamin B12.