In the course of screening for novel pharmacologically active microbial products from fermentations of soil microorganisms, the structure of a thiostrepton-type antibiotic, Sch 18640 was reported2). Several other studies related to thiostrepton-type molecule have also been reported3~8). Presently, we report our studies of a first diasaccharide containing sulfur-rich peptide antibiotic, Sch 40832. Sch 40832 (1) is a minor component of the antibiotic complex (also referred to as 13~384 complex) produced by Micromonosporia carbonecea var africana (ATCC 39149). Taxonomy, fermentation, isolation and characterization have been reported9). Solvent extraction of the fermentation broth followed by chromatography afforded two everninomicins (Sch 27899 and 27900), chloramphenicol, Sch 40832, a diketopiperazine and other minor components. The structure elucidation10) of Sch 27899 and 27900 and in vitro activity11) of the former have recently been reported. The in vitro activity of Sch 40832 was determined using a disc-diffusion agar plate assay against gram positive bacteria following established procedures. Results indicated that Sch 40832 had potent activity in the range of 0.1~1.0mcg/ml.