2-butanol mas emulsified with several kinds of surfactants and esterified by indirect electrolysis using a redox couple I+/I-as a mediator. For any kind of surfactant, relatively large amount of carboxylic acid was by-produced besides the ester. The ester yield is affected by kind of surfactant and concentration. When anionic surfactant SDS and nonionic surfactant Triton X were used, ester yield increased regularly with an increase in their concentration to about three times as much as that obtained without a surfactant. In contrast, the carboxylic acid yield shows a maximum against surfactant concentration and maximum values are dependent upon the kind of surfactant used. The changes in electrolysis behavior with addition of surfactants are explained roughly in terms of HLB values of the surfactants and change in the rate-controlling step.