Almost the entire 16S rRNA gene sequences of some strains of CDC group 1 and group 1-like coryneform bacteria, isolated from human sources, were determined. Comparative analysis of the rRNA sequence data revealed that both groups of coryneforms belong to the genus Actinomyces. On the basis of the present molecular findings and previous biochemical studies, we propose a new Actinomyces species, Actinomyces neuii sp. nov., containing Actinomyces neuii subsp. neuii subsp. nov. for CDC group 1 coryneform bacteria and Actinomyces neuii subsp. anitratus subsp. nov. for CDC group 1-like coryneform bacteria.