A novel aerobic, Gram-negative bacterium, designated strain CM41_14b(T), was isolated from surface waters in the coastal north-western Mediterranean Sea. Cells were non-motile, straight rods, 2.6 mu m long and 0.7 mu m wide and formed pale-orange colonies on marine agar medium. The G + C content of the genomic DNA was 39 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence placed the strain within the genus Balneola (phylum Bacteroidetes). On the basis of 16S rRNA gene sequence comparisons, and physiological and biochemical characteristics, the isolate represents a novel species for which the name Balneola alkaliphila sp. nov. is proposed. The type strain is CM41_14(T) (=DSM 19538(T)=CIP 109603(T)=OOB 103(T)).