In the course of a screening program for new antibiotics, we isolated a new depsipeptide antibiotic, depsidomycin (1) from the cultured broth of Streptomyces lavendofoliae MI951-62F2. It is primarily active against Gram-positive microorganisms and has immunosuppressive activity. Now we report the fermentation, isolation, physico-chemical properties, biological activities and the structure determination of depsidomycin.