Wine strains belonging to the genus Leuconostoc were classified as Leuconostoc oenos by Garvie in 1967, and this name was confirmed on the Approved Lists of Bacterial Names in 1980. L. oenos is distinguished from other Leuconostoc spp. by its growth in acidic media, by its requirement for a growth factor in tomato juice, and by a number of carbohydrate fermentation characteristics. In addition, the results of a total soluble cell protein analysis, an electrophoretic analysis of NAD-dependent D-(-)-lactate dehydrogenase, 6-phosphogluconate dehydrogenase, and alcohol dehydrogenase, and an analysis of cross-reactivity with anti-glucose-6-phosphate dehydrogenase and anti-NAD-dependent D-(-)-lactate dehydrogenase performed with other Leuconostoc spp. clearly indicated that L. oenos should be distinguished from the other Leuconostoc species. Phylogenetic studies, in particular 16S and 23S rRNA sequencing studies, have revealed that L. oenos represents a distinct subline that is separate from other Leuconostoc spp. and lactic acid bacteria. In view of the phenotypic and phylogenetic distinctiveness of L. oenos, we propose that this species should be assigned to a new genus as Oenococcus oeni [corrig.] gen. nov., comb. nov. The type strain of O. oeni is NCDO 1674 (= ATCC 23179).