The overall mortality of patients with ARF has remained distressingly high. Factors responsible for this are reviewed: While improved prophylaxis, decreased occurrence of septic abortion and mismatched transfusions and the use of better contrast media have contributed to lower its incidence, >> prolongation << of life in intensive care units, >> extreme << surgical procedures, multimorbidity of elderly patients and the frequent use of nephrotoxic drugs are factors responsible for a raised incidence. The introduction of intensive-care measurements, >> prophylactic << dialysis or >> protective << medication in order to alter the course of established ARF has been of limited value only. Multiple organ failure - especially in patients with polytrauma or preexisting multimorbidity - is of high negative impact and remains a major therapeutic problem.