A novel aerobic, non-spore-forming, non-motile, catalase- and oxidase-positive, Gram-stain-negative, coccoid to short-rod-shaped bacterial strain, designated YW11(T), was isolated from soil under long-term application of triazophos. The strain was able to hydrolyse triazophos. Strain YW11(T) grew at 15-40 °C (optimum at 28 °C), at pH 5.0-8.0 (optimum at pH 7.5) and with 0-5.0 % (w/v) NaCl (optimum at 0.5 %). The major respiratory quinone was ubiquinone 10 (Q-10) and the major cellular fatty acids were C18 : 1ω7c, C16 : 0, C18 : 1 2-OH and C18 : 0. The genomic DNA G+C content of strain YW11(T) was 69.6±0.5 mol%. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine, an unknown glycolipid and two unknown aminolipids. Phylogenetic analysis based on 16S rRNA gene sequence comparison revealed that strain YW11(T) was a member of the genus Roseomonas, and showed the highest sequence similarity to Roseomonas cervicalis KACC 11686(T) (97.9 %) and Roseomonas aestuarii KACC 19645(T) (97.8 %) and then to Roseomonas ludipueritiae KACC 13843(T) (96.9 %). Strain YW11(T) showed low DNA-DNA relatedness with R. cervicalis KACC 11686(T) (32.3±2.9 %), R. aestuarii KACC 16549(T) (28.2±2.6 %) and R. ludipueritiae KACC 13843(T) (30.2±2.6 %). Based on the results of phylogenetic analysis and DNA-DNA hybridization, the whole-cell fatty acid composition as well as biochemical characteristics, strain YW11(T) was clearly distinguished from all recognized species of the genus Roseomonas and should be assigned to a novel species of the genus Roseomonas, for which the name Roseomonas rhizosphaerae sp. nov. is proposed. The type strain is YW11(T) ( = KACC 17225(T) = CCTCC AB2013041(T)).