Following bone marrow transplantation, acute renal failure and proteinuria are common complications with a high mortality, particularly in patients requiring hemodialysis. Incidence, potential predisposing factors, and outcome of acute renal complications in patients with hematological malignancies receiving autologous peripheral blood stem cell transplantation were prospectively studied in 53 patients. Eight patients developed acute renal failure. Three of them required hemodialysis. Of all patients with acute renal failure, only those requiring hemodialysis died, due to nonrenal causes. Only 1 of the 45 patients without renal failure died. Mild proteinuria of predominantly tubular origin occurred in 16 patients, in 3 with and in 13 without acute renal failure. As predisposing factors for acute renal failure were identified: renal hypoperfusion due to systemic inflammatory response syndrome, sepsis or septic shock, and combined administration of nephrotoxic drugs. Especially those patients receiving high numbers of nephrotoxic drugs in combination with renal hypoperfusion were likely to develop acute renal failure. These results suggest that patients receiving high-dose chemotherapy and autologous peripheral blood stem cell transplantation have a low risk of developing acute renal failure and proteinuria.