The taxonomic position of four Gram-negative, rod-shaped, golden-yellow-coloured bacteria isolated from marine sediments was determined. Analysis of the almost complete 16S rRNA gene sequences indicated that these isolates belong to the family Flavobacteriaceae. An unclassified bacterium, NBRC 15975, was found to be the closest relative, showing 16S rRNA gene sequence similarity of 93 %; other related genera shared only 87.9-90.5 % similarity. In contrast, the four isolates shared high levels of 16S rRNA gene sequence similarity (99.3-99.7 %) and high DNA-DNA reassociation values (93-104 %). The isolates could be differentiated phenotypically from other genera by the abilities to reduce nitrate and to degrade gelatin, casein and starch. The only respiratory quinone was MK-6, and the major fatty acids were iso-C(15 : 0), iso-C(15 : 1), anteiso-C(15 : 0), iso-C(17 : 1)omega9c and iso-C(17 : 0) 3-OH. The DNA G+C content was 38-40 mol%. Differentiating phenotypic characteristics and large phylogenetic distances between the isolates and previously published genera indicated that the isolates constitute a novel genus, for which the name Sediminicola gen. nov. is proposed. The type species is Sediminicola luteus sp. nov. (type strain CNI-3T = NBRC 100966T = LMG 23246T).