A Gram-staining-negative, rod-shaped, motile bacterium, designated WD12T, was isolated from a rotten tree at Chungbuk National University, South Korea. WD12T grew optimally at 30-37 °C and pH 7.0-7.5 and could assimilate arbutin and potassium-5-ketogluconate. The major cellular fatty acid were iso-C16 : 0, C16 : 0, cyclo C17 : 0, iso-C15 : 0, summed features 3 (comprising C16 : 1ω7c/iso-C15 : 0 2-OH) and anteiso-C15 : 0. The major polar lipids consisted of phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The major respiratory quinone was ubiquinone-8 (Q-8). The G+C content of the genomic DNA was 69.1 %. The results of phylogenetic and comparative analysis based on the 16S rRNA gene sequence indicated that WD12T formed a tight phylogenetic lineage with Pseudoxanthomonas mexicana AMX 26BT and Pseudoxanthomonas japonensis 12-3T of the the genus Pseudoxanthomonas in the family Xanthomonadaceae. Sequence similarity to other members of the genus Pseudoxanthomonasranged from 98.6 % (P. mexicana AMX 26BT) to 95.1 % (Pseudoxanthomonas taiwanensis CB-226T). DNA-DNA relatedness between WD12T and eight type strains of species of the genus Pseudoxanthomonasshowing more than 97 % 16S rRNA sequence similarity were 6±0-26±1 %. On the basis of the evidence from this polyphasic study, WD12T represents a novel species of the genus Pseudoxanthomonas, for which the name Pseudoxanthomonas putridarboris sp. nov. is proposed. The type strain is WD12T (=KACC 15045T=LMG 25968T).