Abstract: Koji is produced from soybean hypocotyl as a koji substrate by: (a) soaking the soybean hypocotyl in water for a period ranging from 1 min to 30 hrs; (b) steaming the soaked soybean hypocotyl at a temperature ranging from 90 to 140° C.; (c) inoculating Bacillus sp., Aspergilllus sp or a mixture thereof to the steamed soybean hypocotyl in an amount ranging from 0.01 to 10 wt % based on the total weight of the soybean hypocotyl; and (d) culturing the inoculated soybean hypocotyl at a temperature ranging from 15 to 55° C., a relative humidity ranging from 40 to 100% and at a pH ranging from 3 to 10 for a period ranging from 1 to 8 days.