Cultures of blood and/or cerebrospinal fluid from four of 1,013 bone marrow transplant recipients treated at our center between January 1972 and April 1994 were positive for Listeria monocytogenes. The overall occurrence of listeriosis was 0.39 case per 100 transplantations. Allograft recipients had received prior treatment with parenteral methylprednisolone, thus supporting an association between listeriosis and corticosteroids. Treatment with parenteral ampicillin (200 mg/[kg.d]) and gentamicin is recommended for a minimum of 3 weeks before oral therapy. Two patients with penicillin allergies in this study failed to respond to chloramphenicol-based therapeutic regimens. Recurrent meningitis occurred in two patients, and the therapeutic use of intrathecal gentamicin/vancomycin did not confer a survival advantage (i.e., the patients did not survive).