Purpose To determine mortality rates in patients with acute renal failure during the past decades. Methods We performed a MEDLINE search using the keywords “acute renal failure” crossed with “outcome,” “mortality,” “ICU,” “critically ill” or “prognosis” in the period from January 1970 to December 2004. Abstracts and full articles were eligible if mortality rates were reported. We also reviewed the bibliographies of available studies for further potentially eligible studies. The dates of the observation period for each study and not the publication dates were considered for the analysis, so the earliest data were from 1956. Results Of 85 articles fulfilling the criteria, 5 were excluded because of duplicate publications using the same database, so that 80 were included in our review with a total of 15 897 patients. Mortality rates in most studies exceeded 30%, and there was no consistent change over time. Conclusion Despite technical progress in the management of acute renal failure over the last 50 years, mortality rates seem to have remained unchanged at around 50%.