A Gram-negative, non-motile, non-spore-forming bacterial strain, S1-3(T), was isolated from a tidal flat sediment on the west coast of Korea and its taxonomic position was investigated. Strain S1-3(T) grew optimally at 30 degrees C and in the presence of 2 % (w/v) NaCl. Strain S1-3(T) contained MK-7 as the predominant menaquinone and C(16 : 1)omega7c and/or iso-C(15 : 0) 2-OH and iso-C(15 : 0) as the major fatty acids. The DNA G+C content was 41.4 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain S1-3(T) fell within the clade comprising Algoriphagus species, clustering with Algoriphagus halophilus IMSNU 14013(T), with which it exhibited 99.6 % 16S rRNA gene sequence similarity. The 16S rRNA gene sequence similarity between strain S1-3(T) and the type strains of other Algoriphagus species was 94.0-97.1 %. Differential phenotypic properties and phylogenetic and genetic distinctiveness of strain S1-3(T) demonstrated that this strain is distinguishable from the other Algoriphagus species as well as A. halophilus. On the basis of phenotypic, chemotaxonomic, phylogenetic and genetic data, strain S1-3(T) is considered to represent a novel species of the genus Algoriphagus, for which the name Algoriphagus lutimaris sp. nov. is proposed. The type strain is S1-3(T) (=KCTC 22630(T) =CCUG 57608(T)).