A Gram-staining-negative, strictly aerobic bacterial strain, designated SM-6T, was isolated from a sea tidal flat of the Dangjin bay, South Korea. Strain SM-6T was able to degrade a broad range of aliphatic hydrocarbons. Cells were catalase- and oxidase-positive and non-motile rods. Growth of strain SM-6T was observed at 10-37 °C (optimum, 20-25 °C), at pH 5.5-9.0 (optimum, pH 6.5-7.5) and in the presence of 0-10 % (w/v) NaCl (optimum, 2-3 %). The only isoprenoid quinone detected was ubiquinone-8 (Q-8). C17:1ω8c, C11:0 3-OH, summed feature 3 (comprising C16:1ω7c and/or C16:1ω6c), C9:0 3-OH and C10:0 3-OH were observed as the major cellular fatty acids and phosphatidylethanolamine, phosphatidylglycerol and four unidentified lipids were detected as polar lipids. The G+C content of the genomic DNA was 47.5 mol%. Strain SM-6T was most closely related to Pseudomaricurvus alkylphenolicus KU41GT (95.5 %), Maricurvus nonylphenolicus KU41ET (94.4 %) and Pseudoteredinibacter isoporae SW-11T (94.3 %), based on 16S rRNA gene sequences, and phylogenetic analyses showed that strain SM-6T formed a phyletic lineage distinct from the closely related genera. On the basis of phenotypic, chemotaxonomic and molecular features, strain SM-6T represents a novel genus and species of the order Alteromonadales in the class Gammaproteobacteria, for which name Aestuariicella hydrocarbonica gen. nov., sp. nov. is proposed. The type strain is SM-6T ( = KACC 18121T = JCM 30134T).