Antimicrobial activities of marinex and preservative characteristics of soybean curds soaked in diluted marinex were investigated. One hundred ml of marinex showed antimicrobial activities against Streptococcus mutans, Bacillus subtilis, Pseudomonas aeruginosa, Salmonella typhimurium, Escherichia coli and Escherichia coli O-157 on a paper disc test. The growth of the microorganisms were inhibited with 200${mu}{ell}/m{ell}$ of culture media. pH of soybean curd treated with marinex decreased to 1 day and then slowly increased as storage time increase, which was higher than control after 1 day of storage and lower after that time. Little difference was observed between control and marinex treated soybean curd in color. Hardness and chewiness of the treated sample were higher than those of the control. The numbers of E. coli and bacteria of the treated sample were lower than those of control during storage. The inhibition of the growth of E. coli and bacteria was dose dependent.