Two enterococcal strains LMG 16607(T) and LMG 16612 originating from sea water were analysed in a polyphasic taxonomic study. Both strains, assigned as Enterococcus sp. in the BCCM/LMG culture collection, possessed analogous protein profiles, but these were different from all other enterococcal species. 16S rRNA gene sequence analysis of one strain showed the highest similarity, 96.9-96.1%, with its closest phylogenetic neighbours Enterococcus saccharolyticus, Enterococcus sulfureus, Enterococcus saccharominimus and Enterococcus italicus. Further genomic analysis by (GTG)(5)-PCR fingerprinting and sequence analysis of the housekeeping gene phenylalanyl-tRNA synthase (pheS) and distinct biochemical features confirmed that the two strains represent a novel enterococcal species for which the name Enterococcus aquimarinus sp. nov. is proposed. The type strain is LMG 16607(T) (=CCM 7283(T)).