Six strains of Streptomyces, all producing sclerothricin and forming sclerotic granules on their vegetative mycelium, have been isolated from soil samples of Japan. A comparison of the characteristics of these strains with related Streptomyces indicates that these should belong to a new species, named by us as S. sclerogranulatus SHIMAZU et YONEHARA sp. nov. with No.7672-MC4 as the type strain. © 1969, JAPAN ANTIBIOTICS RESEARCH ASSOCIATION. All rights reserved.