Bacillus subtilis is a predominant species of bacteria found abundantly in Korean soy sauce, soybean paste, and meju (Korean fermented soybean brick), which is a substrate for soy sauce and soybean paste production. This study was conducted to investigate the possibility of an inhibitory effect of meju-derived B. subtilis on the growth and aflatoxin production of Aspergillus parasiticus. Microorganisms were grown in yeast-extract sucrose broth and incubated at 28℃ for 12 days. Aflatoxins were quantitated using high-performance liquid chromatography. A substantial inhibition of A.