A polyphasic taxonomic approach was applied to the study of a Gram-negative bacterium (B2(T)) isolated from soil by selective enrichment with pentachlorophenol. 16S rRNA gene sequence analysis of strain B2(T) showed that the strain belongs to the genus Achromobacter within the Betaproteobacteria. The 16S rRNA gene sequence displayed more than 99 % similarity to the sequences of the type strains of all species of Achromobacter, with the highest sequence similarity to those of Achromobacter spanius CCM 7183(T) and A. piechaudii CCM 2986(T) (99.8 %). On the basis of phylogenetic analysis, genomic DNA-DNA relatedness and phenotypic characteristics, including chemotaxonomic (cellular fatty acid profile) analysis, a novel species is proposed, Achromobacter marplatensis sp. nov., with the type strain B2(T) ( = CCM 7608(T) = CCUG 56371(T) = CECT 7342(T)).