A novel actinomycete producing 2-allyloxyphenol, designated strain MS1/7T, was isolated from sediments of the Sundarbans mangrove forest, India. Growth on International Streptomyces Project (ISP) media 2, 3, 4, 5 and 7 produced olive green to grey aerial hyphae that carried smooth-surfaced spores in a flexuous (Rectiflexibiles) arrangement. The strain contained ll-diaminopimelic acid, but no diagnostic sugars in whole-cell hydrolysates. Hexa-, octa- and a minor amount of tetra-hydrogenated menaquinones with nine isoprene units [MK-9 (H4, H6, H8 and H10)] were present as isoprene analogues. Diagnostic phospholipids were phosphatidylethanolamine and diphosphatidylglycerol. The predominant fatty acids were anteiso-C15 : 0 (34.80 %), iso-C16 : 0 (16.45 %), C16 (10.53 %) and anteiso-C17 : 0 (10.92 %). The strain showed greater than 99 % 16S rRNA gene sequence similarity to the type strains of several recognized species of the genus Streptomyces, but in the phylogenetic tree based on 16S rRNA gene sequences it formed a distinct phyletic line and demonstrated closest relationships to viomycin-producers (Streptomyces californicus NRRL B-1221T, Streptomyces floridae MTCC 2534T and Streptomyces puniceus NRRL B-2895T). However, strain MS1/7T could be distinguished from these and other closely related species based on low levels of DNA–DNA relatedness (<44 %) and disparate physiological features, principally amino acid utilization and growth in NaCl. Strain MS1/7T is therefore suggested to represent a novel species of the genus Streptomyces, for which the name Streptomyces sundarbansensis sp. nov. is proposed. The type strain is MS1/7T ( = MTCC 10621T = DSM 42019T).