Isolation of black-pigmented Corynebacterium species from human clinical samples has been reported, although rarely. Review of the medical literature revealed 3 reports of culture isolation of these unusual bacteria. All were recovered from the female genital tract, and 1 case was associated with spontaneous abortion. Genetic characterization of these isolates indicates that they are similar and probably represent a novel pathogen in the genus Corynebacterium. We report 3 additional bacterial isolates sharing similar phenotypic and/or genotypic characteristics that were recovered from the genital tract of women who had complications of pregnancy. Similarities in these cases suggest that this newly recognized Corynebacterium species might be an opportunistic pathogen in pregnancy.