An unusual black-pigmented coryneform bacterium was isolated from the urogenital tract of a woman who experienced a spontaneous abortion during month 6 of pregnancy. Biochemical and chemotaxonomic analyses demonstrated that the unknown bacterium belonged to the genus Corynebacterium. Phylogenetic analysis based on 16S rRNA sequences (GenBank accession no. AF220220) revealed that the organism was a member of a distinct subline which includes uncultured Corynebacterium MTcory 1P (GenBank accession no. AF115934), derived from prostatic fluid, and Corynebacterium CDC B8037 (GenBank accession no. AF033314), an uncharacterized black-pigmented coryneform bacterium. On the basis of chemotaxonomic and phylogenetic evidence, this organism probably represents a new species and is most closely related to the uncharacterized Centers for Disease Control and Prevention group 4 coryneforms. Our strain is designated CN-1 (ATCC 700975).