An endophytic actinomycete, strain YIM 65188(T), was isolated from surface-sterilized tissue of Sedum sp. collected from Yunnan province, south-west China, and characterized by using a polyphasic approach. Analysis of the 16S rRNA gene sequence showed that strain YIM 65188(T) is a member of the genus Streptomyces and exhibited 97.5 and 96.3 % gene sequence similarities to Streptomyces specialis GW41-1564(T) and Streptomyces hainanensis YIM 47672(T), respectively, whereas low sequence similarity values (<95.2 %) distinguished strain YIM 65188(T) from all other Streptomyces species with validly published names. Strain YIM 65188(T) had a unique menaquinone composition, with the predominant quinones being MK-11(H(6)) and MK-10(H(6)), with moderate amounts of MK-10(H(8)), MK-11(H(8)), MK-9(H(8)), MK-11(H(4)), MK-9(H(6)) and MK-10(H(4)). Similarly, the closest phylogenetic relative, S. specialis GW41-1564(T), also had an unusual quinone composition, with the predominant menaquinones MK-10(H(4)) and MK-10(H(6)) and minor amounts of MK-9(H(4)) and MK-9(H(6)). The DNA-DNA hybridization value between strain YIM 65188(T) and S. specialis GW41-1564(T) was 42.7 %. On the basis of phenotypic and phylogenetic characteristics, strain YIM 65188(T) was identified as a novel species of the genus Streptomyces for which the name Streptomyces sedi sp. nov. is proposed, with YIM 65188(T) (=CCTCC AA 208020(T) =DSM 41942(T)) as the type strain.