In the course of our screening for new insecticidal compounds from microbial metabolites, a novel destruxin derivative, [Phe3, N-MeVal5] destruxin B (1, Figure 1), was isolated from the fermentation broth of a Beauveria sp. Spectroscopic analyses revealed that compound 1 was a new cyclic hexadepsipeptide belonging to the destruxin family that has shown a variety of biological activities including insecticidal, phytotoxic, nematicidal, and immunosupressant activities1-5). In this paper, we report the fermentation, isolation, and structure determination of [Phe3, N-MeVal5] destruxin B (1).