['To see if it is possible to predict mortality in isolated post-traumatic acute renal failure.', 'Retrospective study 1984-1990 inclusive.', 'Teaching hospital, South Africa.', 'Thirty-nine patients who developed isolated post-traumatic acute renal failure out of 106526 admissions for trauma.', 'Standard aggressive management of traumatic injury and acute renal failure.', 'Death.', 'Fifteen of the 39 patients who developed post-traumatic acute renal failure died (39%). Blunt trauma from assaults was a major cause of acute renal failure (16/39, 41%). Hypotension and hyperkalaemia were the two main predictors of death having a mortality of 63% and 52%, respectively.'] Is prognosis in posttraumatic acute renal failure adversely influenced by hypotension and hyperkalaemia?