A Gram-positive, non-motile, rod-shaped actinomycete strain, designated SSW1-57T, was isolated from a dried seaweed sample from the coast of Jeju Island, Republic of Korea and subjected to a polyphasic taxonomic study. A neighbour-joining tree based on 16S rRNA gene sequences showed that the organism was related to members of the family Nocardioidaceae and formed a separate branch at the base of a taxon encompassing members of the genus Aeromicrobium, whereas it occupied an intermediate position between Aeromicrobium alkaliterrae-Aeromicrobium marinum and Aeromicrobium erythreum-Aeromicrobium fastidiosum clusters in maximum-parsimony and maximum-likelihood trees. The phylogenetic association of the isolate with the genus Aeromicrobium was supported by the following chemotaxonomic properties: ll-diaminopimelic acid in the peptidoglycan, MK-9(H4) as the major menaquinone and major fatty acids cis-9-octadecenoic acid, hexadecanoic acid, 10-methyl octadecanoic acid and 2-hydroxy hexadecanoic acid. The polar lipid profile contained phosphatidylinositol, diphosphatidylglycerol and phosphatidylglycerol. Levels of 16S rRNA gene sequence similarity between the novel organism and the type strains of the four recognized Aeromicrobium species were in the range 96.5-96.7 %. On the basis of phylogenetic analyses and phenotypic data, it is proposed that the organism should be classified as representing a novel species of the genus Aeromicrobium, with the name Aeromicrobium tamlense sp. nov. The type strain is SSW1-57T (=JCM 13811T=NRRL B-24466T).