Recently, Etiella behrii has been identified as a pod borer of soybean in Indonesia. This species had been presumably confused with E. zinckenella due to their similarity in external characters. We, therefore, compared the characteristics and sex pheromone between the two Etiella species. They could be accurately discriminated based on some external characters at both larval and adult stages, without examination of their genitalia. Duration of developmental stage of the insects reared on an artificial diet was 8 days longer in E. behrii than in E. zinckenella at 25°C. Premating period was 3 days longer in E. behrii than in E. zinckenella. Other biological data concerning mating and oviposition were similar between the two species. The sex pheromone of E. behrii was found to be a mixture of (E)-9-dodecenyl acetate (E9-12:Ac), (Z)-11-tetradecenyl acetate (Z11-14: Ac), dodecyl acetate (12:Ac), and (E)-11-tetradecenyl acetate (E11-14:Ac). Z11-14:Ac and E11-14:Ac are the common components in the two species. E9-12Ac and 12Ac in E. behrii, and 14:Ac and Z9-14:Ac in E. zinckenella could be key components in reproductive isolation between the two species. Moreover, the optimum dose of the mixture for capturing E. behrii males was much smaller than that for E. zinckenella males.