Asymmetric induction and diastereomeric ratio in the enzymatic oxygenation of various sulfides to the corresponding sulfoxides with hepatic mirosomal cytochrome P-450 obtained from phenobarbital pretreated rabbit were investigated in comparison with those of nonenzymatic oxidation with m-chloroperbenzoic acid and sodium metaperiodate. While substantial asymmetric inductions were observed in the sulfoxides formed by the enzymattc oxygenations, diastereomeric ratios of the sutfoxides formed were also quite different from those obtained by oxidation with m-chloroperbenzoic acid and sodium metaperiodate.