A novel, Gram-stain-negative marine bacterium, designated GH2-6^T, was isolated from a rhizosphere mudflat of a halophyte (Carex scabrifolia) collected in Gangwha Island, the Republic of Korea. The cells of the organism were strictly aerobic, oxidase- and catalase-positive, non-flagellated rods. Growth occurred at 20-45°C, pH 5-10, and 0.5-9 (w/v) NaCl. The requirement of Na⁺ for growth (0.5-3%) was observed. The major respiratory quinone was Q-10. The major polar lipids were phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, an aminolipid and a glycolipid. The predominant fatty acids were C_18:1ω7c, C_18:0, C_16:0, C_19:0 cyclo ω8c, C_18:1ω7c 11-methyl and summed feature 2 (C_14:0 3-OH and/or C_16:1 iso I). The genome size was 4.45 Mb and the G+C content of the genomic DNA was 61.9 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain GH2-6^T belonged to genus Martelella and formed a tight cluster with M. radicis BM5-7^T and M. endophytica YC6887^T. Levels of 16S rRNA gene sequence similarity between the novel isolate and members of the genus were 99.3-95.5%, but strain GH2-6^T possessed an extended loop (49 nucleotides in length) between positions 187 and 213 of the 16S rRNA gene sequence (E. coli numbering). DDH values in vitro between the novel isolate and the closest relatives were 23.2±12.8-46.3±5.2%. On the basis of polyphasic data presented in this study, the type strain GH2-6^T (= KACC 19403^T = KCTC 62125^T = NBRC 113212^T) represents a novel species of the genus Martelella for which the name Martelella lutilitoris sp. nov. is proposed.