The taxonomic position of a Streptomyces isolate, strain M1463(T), recovered from the rhizosphere of Robinia pseudoacacia was established in a polyphasic study. The organism had chemical and morphological markers that were consistent with its classification in the Streptomyces violaceusniger clade. This assignment was confirmed by 16S rRNA gene sequence data, which also showed that the strain formed a distinct subclade together with Streptomyces malaysiensis DSM 41697(T). However, the two strains were readily distinguished on the basis of DNA relatedness and phenotypic data. The combined genotypic and phenotypic data show that strain M1463(T) should be recognized as a representative of a novel species in the Streptomyces violaceusniger clade, for which the name Streptomyces samsunensis sp. nov. is proposed. The type strain of S. samsunensis is M1463(T) ( = DSM 42010(T) = NRRL B-24803(T)).