During the search for novel neurokinin receptor inhibitors, a cyclodepsipeptide (Sch 217048) was isolated from an unidentified fungal fermentation broth with selective NK2 antagonist-type activity. The fermentation broth was extracted with EtOAc at pH ~6.5, and Sch 217048 was purified by NK2 assay-guided fractionation using gel filtration (Sephadex LH-20/MeOH) and reverse phase preparative HPLC (Waters Deltapak C-18, 3.0 × 30 cm, ACN:0.05% TFA = 35:65). The molecular formula of Sch 217048 was determined to be C57H88N10O14 by HRFABMS. Extensive NMR analyses (1H, 13C, COSY, HOHAHA, HETCOR, HMBC, HMQC-TOCSY) and FABMS-MS analysis of its base hydrolysis products revealed its structure, which contains amino acids Phe, Pro, Gly, MeVal, MeGln, Ile, pipecolic acid (Pip), Val, MeGlu, and 2-hydroxy-3-methylpentanoic acid (HMP). Biological activity assays showed that Sch 217048 exhibited selectivity for the NK2 receptor with an IC50 value of 50 nM, while the IC50 for the NK1 receptor was >1000 nM.