A novel Gram-stain-positive, aerobic, catalase-positive, oxidase-negative, non-motile, and rod-shaped bacterium with ibuprofen-degrading capacity, designated DM4 T , was isolated from the sewage of a wastewater treatment plant (WWTP) in Guangzhou city, China. Strain DM4 T grew optimally at 0% (w/v) NaCl, pH 5.0-7.0, and 30 °C, forming white colonies on trypticase soy agar. C 18:1 ω9c, C 18:2 ω9.12c and C 15:1 ω10c were the predominant fatty acids. Results of 16S rRNA gene alignment and phylogenetic analysis indicated that strain DM4 T belonged to the genus Patulibacter, was closely related to Patulibacter medicamentivorans DSM 25692 T (98.5%) and P. brassicae KCTC 39817 T (98.1%). Strain DM4 T had a genome size of 5.33Mbp, and the DNA G + C content was 75.0%. The average nucleotide identity (ANI), average amino acid identity (AAI), and digital DNA-DNA hybridisation (dDDH) values between strain DM4 T and P. medicamentivorans were 85.2%, 83.9%, and 29.0% respectively, while those between strain DM4 T and P. brassicae were 78.5%, 71.3%, and 22.2%, respectively. Strain DM4 T could significantly degrade ibuprofen by almost 80% after 84 h of incubation, and the degradation kinetics was well fitted with the first-order kinetics. Evidence from phenotypic, phylogenetic and chemotaxonomic analyses support that strain DM4 T (= GDMCC 1.4574 T = KCTC 59145 T ) represents a new species of the genus Patulibacter, for which the name Patulibacter defluvii sp. nov. is proposed.