Six strains isolated from the intestines of juvenile turbot in a fish hatchery in the north of Spain were found to be phenotypically members of the genus Vibrio. However, the phenotypic traits of these organisms did not place them in any of the currently known Vibrio species. These isolates formed an homogeneous group in which the DNA-DNA similarity values (the differences between the thermal denaturation midpoints of the homologous and heterologous duplexes) with reference strain A089T (T = type strain) ranged from 0 to 1.7 degrees C. The results of a 16S rRNA sequence analysis of A089T placed this strain in the genus Vibrio in the gamma subclass of the Proteobacteria. The closest relative is Vibrio aestuarianus, with a sequence similarity of 97.8%. This group of strains can be easily differentiated from the other Vibrio species by their clear phenotype. We propose the name Vibrio scophthalmi sp. nov. for these strains; the type strain is strain A089 (= CECT 4638).