The marine environment has recently been described as a source of novel chemical diversity for drug discovery,1 as many bioactive substances are isolated from marine organisms including phytoplankton, algae, sponges, tunicates and mollusks.2,3 Our group has also reported the isolation of azaspiracid-24 and JBIR-445 from marine sponges. Microorganisms from marine habitats,6,7 especially actinobacteria, also constitute a promising untapped resource of novel compounds and are receiving special attention. Compared with higher organisms, microorganisms can be easily maintained under laboratory conditions ensuring a constant and inexpensive supply of their secondary metabolites. Moreover, compounds originally thought to be produced by a marine organism were later found to be produced by hostassociated microorganisms.8 A significant body of work has emerged in the past 10 years on the isolation of actinobacteria from marine habitats and their screening has yielded several novel bioactive compounds.9–11Our group recently engaged in the isolation of microorganisms from marine sources including fungi and actinobacteria. Some of the isolated fungi were found to produce novel compounds, namely, JBIR-27, -28,12 -15,13 -37 and -38.14 Among actinobacteria, many novel members of the genus Streptomyces were isolated from a marine sponge Haliclona sp.15 Interestingly, many of the isolated strains required salt for their optimal growth. The requirement of salt by these strains may indicate their marine origin. One such salt-requiring strain Streptomyces sp. NBRC 105896 was isolated from Haliclona sp. When tested for the production of novel secondary metabolites, Streptomyces sp. NBRC 105896 produced a novel teleocidin analog designated as JBIR-31 (1) with eight known compounds. This paper describes the fermentation, isolation, structure elucidation and briefly the biological activity of 1.