Transesterification of rice bran oil was investigated to produce the bio-diesel oil. Experimental conditions in-cluded molar ratio of rice bran oil to alcohol(1:3, 1:5 and 1:7), concentration of catalyst used(0.5, 1.0 and 1.5wt%), types of catalysts(sodium methoxide, NaOH and KOH), reaction temperatures(30, 45 and 60℃) and types of alcohols(methanol, ethanol and butanol). The conversion of rice bran oil increased with the alcohol mixing ratio and with the reac-tion temperature. Sodium methoxide was the most effective among the catalysts. The conversion was increased with the concentration of catalyst, but slightly increased over 1.0wt%. The best conversion was obtained using methanol with so-dium methoxide. In the case, 98% conversion was achieved within 1hr. The physical properties of rice bran oil for diesel fuel can be significantly improved by transesterification reaction.