Species of Corynebacterium other than C. diphtheriae generally are considered to be contaminants when encountered in cultures of clinical material. These organisms inhabit the skin and mucous membranes of the upper respiratory tract, urethra, and vagina. Coryneform organisms include Listeria, Erysipelothrix, and Kurthia as well as Corynebacterium. Erysipelothrix can cause infections in otherwise normal persons (1, 2). Although Listeria causes infection in normal hosts, most infections occur in immunocompromised persons (3, 4). Diphtheroid infection has been associated with vascular prosthesis or immunosuppression (4–6). Previously reported isolations of Kurthia from clinical material have not clearly established an association with infection (7).