Corynebacterium vaginale is a sexually transmitted organism which was first recognized in 1953. It appears to utilize glycogen stored in vaginal epithelial cells, causing a malodorous vaginal discharge characterized by an abnormally high pH (5.0 to 5.5) and composed mainly of epithelial cells and hordes of bacilli. Infected men are asymptomatic, carry the organism for an unknown period of time, and transmit it through intercourse. The organism requires five B-vitamins, purines, pyrimidines, and a fermentable carbohydrate; neither factors X nor V are required. It is not a member of genus Haemophilus and is not likely to be a Corynebacterium. Appearing mainly Gram-negative, it has many characteristics of Gram-positive organisms including its pattern of sensitivity to antibiotics and the possession of certain enzyme systems. As the cause of bacterial vaginitis, C. vaginale may be the most prevalent sexually-transmitted organism.