A total of 296 episodes of bacteremia due to Enterobacter occurred in 281 patients with cancer between 1972 and 1986. The majority of these episodes were caused by Enterobacter cloacae. Seventy-four percent of the patients developed their infection while in the hospital and 55% had received therapeutic antibiotics during the 10 days preceding the onset of the infection. Enterobacter bacteremia was associated with shock in 24% of the patients and with disseminated intravascular coagulation in only 3%. The overall rate of response to therapy was 79% and increased to 85% during the last 5-year period. Only five patients remained afebrile during their infection, but four of these five died. Only 37% of the patients with shock responded to therapy compared with 93% of the patients without shock. The rate of response to therapy was 86% among patients without pulmonary infection compared with only 53% among those with pulmonary infection. The response rate to therapy with a single antibiotic was 73% and that to therapy with two antibiotics was 85%. As single therapeutic agents aminoglycosides were less effective than beta-lactam agents.