An actinobacterial strain, designated D48(T), was isolated from the rhizosphere soil of a cypress tree collected from Mianyang in Sichuan province, China. The strain was Gram-stain-positive, catalase-positive, oxidase-negative and non-motile, with lysine as the peptidoglycan diagnostic diamino acid and acetyl as the peptidoglycan acyl type. The predominant menaquinone was MK-9(H(2)); small amounts of MK-7(H(2)), MK-10(H(2)) and MK-6 were also present. The major fatty acids were anteiso-C(15:0), anteiso-C(17:0) and iso-C(16:0). The isolate underwent a rod-coccus morphological cycle, had a high DNA G+C content, was aerobic and grew between 12 and 37 °C (optimum, 28 °C). On the basis of the phenotypic and chemotaxonomic analyses, 16S rRNA gene sequence comparisons and DNA-DNA hybridization data, the isolate represents a novel species of the genus Arthrobacter, for which the name Arthrobacter cupressi sp. nov. is proposed. The type strain is D48(T) (=DSM 24664(T)=CGMCC 1.10783(T)).