Comparative analyses of Diaphorobacter polyhydroxybutyrativorans SL-205T and Diaphorobacter nitroreducens NA10BT were conducted for clarifying their taxonomic relationship. The sequences of the 16S rRNA gene and nine housekeeping genes of SL-205T and NA10BT shared high similarities, above 98.8 %. Whole-genomic comparison between the two strains revealed a digital DNA-DNA hybridization estimate of 85.1 % and an average nucleotide identity of 98.3 % that were well above respective recognized thresholds for bacterial species delineation, strongly indicating that they represent the same genomospecies. The metabolic, physiological and chemotaxonomic features of SL-205T were also shown to be congruent with those of NA10BT. Therefore, we conclude that Diaphorobacter polyhydroxybutyrativoransQiu et al. 2015 is a later heterotypic synonym of Diaphorobacter nitroreducens Khan and Hiraishi 2003.