In continuation of the previous $studies^{2{\sim}3)}$, the folate activity levels in 226 Korean food items were determined by a modified microbiological assay with Lactobacillus casei. There was a large variation in folate activity between the different food groups as well as between each individual food. There was also a wide variation in the biologic availability of folate in foods and the different forms of the folate with different foods in varying amounts. Data showed that almost always, foods cooked and/or processed were lower in folate activity than fresh or raw food and the amount of the loss varied greatly in each food. In calculating dietary intake, total rather than free folate activity levels should he used. In addition, loss of folate activity during cooking and processing of foods should be considered as a major concern for appraising diets and food supplies. Among all assayed food items, including Part $I^{2)}}$ and $I^{3)}$, yeast 2800. ug total per 100g the highest folate level. Soybean, spinach, Shepherd's purse and liter of beef and pork had over 100 ug total per 100 g folate activity. Folate ranging over 50 ug total per 100 g was found in all dried legumes, nuts and seeds assayed, Garland Chrysanthemum, leek, mugwort, wafer cress, asparagus, e99 folk and beef kidney. Wheat, sweet Potatoes,dried fungus, green onion, hotrod pepper, lettuce, radish and some fermented soybeen products had considerably higher folate content ranging around 40 ug total per 100 g. Substantial amounts of folate were not found in many food groups, and among specific groups, in part in starch, sweets, fruits, meat, fish, milk, and cooked and processed foods. Soused fish, oils and fats, beverages, liquor and seasonings, other than fermented soybean products, had almost no folate.