A novel actinomycete strain, designated YIM M13705(T), was isolated from a marine sediment sample of the South China Sea and its characteristics were determined by a polyphasic approach. The slowly growing, Gram-stain-positive, aerobic strain produced branched substrate mycelium and aerial hyphae, and no diffusible pigment was produced on the media tested. At maturity, spore chains were formed on aerial hyphae and substrate mycelium was not fragmented. Whole-cell hydrolysates of the strain contained meso-diaminopimelic acid and galactose, glucose, ribose and rhamnose. The predominant menaquinones were MK-9(H4) and MK-10(H2). The polar lipids detected were diphosphatidylglycerol, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylinositol and ninhydrin-positive phosphoglycolipids. The major fatty acid was iso-C(16 : 0). The G+C content of the genomic DNA was 68.2 mol%. On the basis of 16S rRNA gene sequence, the strain was shown to be most closely related to species of the genus Actinophytocola. DNA-DNA hybridization relatedness values (<70%) of the isolate with its closest neighbour Actinophytocola xinjiangensis QAIII60(T) supported classification of the isolate as a representative of a novel species. On the basis of phylogenetic analysis, and phenotypic and genotypic data, it is concluded that the new isolate belongs to a novel species of the genus Actinophytocola, for which the name Actinophytocola sediminis sp. nov. (type strain YIM M13705(T) = DSM 45939(T) = BCRC 16956(T)) is proposed.