In this study commercial nonionic surfactants I and II were used to enhance the solubility of sulfur compounds in the aqueous solution. Commercial nonionic surfactants I-G and II-A were found to have the best solubilizing capacity among the surfactants used during this study. Solubilization of sulfur compounds in the crude oil by commercial I-G was 30.17% at 40℃ and that by commercial II-A was 41.70% at 40℃. Solubilization was increased when alcohol was added as a cosurfactant, presumably due to increase in flexibility of surfactant aggregate packing. It was also found that commercial surfactant I-G hardly affected growth of sulfur reducing bacteria.