A novel marine bacterium, designated strain KMM 6171(T), was subjected to taxonomic analysis by using a polyphasic approach. Colonies were yellow-pigmented and cells were Gram-negative, heterotrophic rods displaying slow gliding motility. 16S rRNA gene sequence analysis indicated that strain KMM 6171(T) was closely related to the genus Algibacter, a member of the family Flavobacteriaceae, with sequence similarity of 96.7-96.8 %. The predominant cellular fatty acids were iso-C15 : 1, iso-C15 : 0, anteiso-C15 : 0, C15 : 0, iso-C15 : 0 3-OH, iso-C17 : 0 3-OH and summed feature 3, comprising C16 : 1omega7c and/or iso-C15 : 0 2-OH. The DNA G+C content was 35.1 mol%. On the basis of the phenotypic, genotypic, chemotaxonomic and phylogenetic data, strain KMM 6171(T) represents a novel species of the genus Algibacter, for which the name Algibacter mikhailovii sp. nov. is proposed. The type strain is KMM 6171(T) (=KCTC 12710(T)=LMG 23988(T)). An emended description of the genus Algibacter based on the new data is also given.