A culture of an actinomyces isolated from a Bikini soil was found to produce a. potent antibiotic substance, which appears to be similar in all respects to streptomycin. The culture was markedly different from S. griseus, the streptomycin-producing organism. It was designated as S. bikiniensis. Since the antibiotic has not been crystallized as yet and its chemical identity with streptomycin not detd., it was tentatively designated as streptomycin II.