Two novel strains, designated KTCe-2T and 7C-9T, isolated from an activated sludge and freshwater sediment, respectively in South Korea, were characterized by a polyphasic approach to clarify their taxonomic positions. Phylogenetic analysis based on 16S rRNA gene sequences indicated that both isolates belong to the genus Lysobacter and are most closely related to 'Lysobacter daecheongensis' Dae 08 (98.5 % and 97.6 % similarity for strains KTCe-2T and 7C-9T, respectively), Lysobacter brunescens KCTC 12130T (98.4 % and 97.2 %), and Lysobacter oligotrophicus JCM 18257T (97.1 % and 96.8 %). The G+C content of the genomic DNA of strains KTCe-2T and 7C-9T was 68.6 % and 71.5 mol%, respectively. Strains KTCe-2T and 7C-9T possessed ubiquinone-8 as the sole respiratory quinone, and a fatty acid profile with iso-C15 : 0 and iso-C16 : 0 as the major fatty acids supported the affiliation of the two strains to the genus Lysobacter. Moreover, the physiological and biochemical results and low DNA-DNA relatedness values allowed the phenotypic and genotypic differentiation of strains KTCe-2T and 7C-9T from other species of the genus Lysobacter with validly published names. Therefore, the two isolates represent two novel species of the genus Lysobacter, for which the name Lysobacter hankyongensis sp. nov. (type strain KTCe-2T = JCM 18204T = KACC 16618T) and Lysobacter sediminicola sp. nov. (type strain 7C-9T = JCM 18205T = KACC 16617T) are proposed.