A total of 251 patients were given 326 courses of high-dose chemotherapy followed by autologous bone marrow transplantation between February 1979 and August 1988. Ninety-one cases of septicaemia developed in 84 patients, 33 of these cases (36%) were due to streptococci. The outcome was fatal for four patients (12.1%). No specific risk factors were identified which might account for this septicaemia and no clinical feature was significantly associated with these cases of bacterial infection. Pulmonary and neurologic septic complications, however, were of very poor prognosis since all patients with these complications died. The high rate of streptococcal septicaemia and the poor outcome for patients with prolonged and profound neutropenia led us to modify our choice of initial broad-spectrum antibiotic therapy.