Three strains, 4M1T, 4M9 and 4M12, were isolated from cotton waste composts. These strains are Gram-negative, aerobic and non-spore-forming rods. 16S rRNA gene sequence comparisons demonstrated that these isolates were clustered phylogenetically within the genus Pseudoxanthomonas and 4M1T revealed sequence similarity levels of 96.9-99.0% to six Pseudoxanthomonas species with validly published names. According to DNA-DNA hybridization, relatedness values between 4M1T and six known Pseudoxanthomonas species were in the range of 52-63%. The DNA G + C content of the strains was 66.6-68.4 mol%. For a more detailed characterization of these strains, the physiological, chemotaxonomic and genotypic properties were evaluated. From the results of this study, the name Pseudoxanthomonas suwonensis sp. nov. is proposed, with the type strain 4M1T (= KACC 11320T = DSM 17175T).