Between 1986 and 1991, 29 patients with malignant lymphomas were treated with total body irradiation and high-dose chemotherapy followed by autologous bone marrow transplantation at the Norwegian Radium Hospital. Owing to treatment-induced bone marrow toxicity, the leucocyte count in peripheral blood rapidly fell to zero. The aplastic phase lasted for 25 days (median). All patients experienced fever in the posttransplant period and needed broad-spectrum antibiotics. 12 patients had documented bacteremia, mostly with Gram-positive isolates. There were seven cases of documented focal infections, and antibiotic-associated colitis was seen in two cases. Other complications included bleedings and skin rashes. Four patients died in the post-transplant period from complications related to the cytotoxic treatment. We discuss guidelines for antimicrobial treatment of suspected and confirmed infections in neutropenic patients.