In a retrospective study, we identified 55 elderly patients with acute renal failure (ARF) admitted to our hospital during an 8-year period from 1985 to 1993. Information about the etiology, complications, laboratory data, and treatment course were obtained from the clinical history. Of the 200 patients with ARF admitted to the hospital during this period, 28% were patients more than 60 years old (41 male and 14 female) with an average age of 68.5 +/- 7 years. The main causes of ARF were sepsis, volume depletion, low cardiac output, arterial hypotension, nephrotoxicity by antibiotics, and obstructive uropathy. The global mortality of elderly patients with ARF was 53%. The mortality rate of the different types of the ARF were: prerenal 35%, intrinsic 64% (oliguric 76%, nonoliguric 50%), and postrenal 40%. Mortality as a result of sepsis occurred in 18 patients (62%), by cardiovascular disease in 4 patients (13%), by acute respiratory failure in 2 patients (7%), and by other causes in 5 patients (18%). In the cases of sepsis, Pseudomonas was detected in 7 cases (39%), Escherichia coli in 2 cases (11%), Gram-negative nonspecific in 3 cases (17%), Klebsiella in 1 case (5%), and in 5 cases (16%), the hemoculture was negative. The patient survival rate was 47% (26 of 55 patients). Of these patients, 19 recovered their normal renal function (73%), but 7 patients remained with renal failure (27%). In conclusion, the global mortality in the elderly patients without considering the types of ARF was 53%. The oliguric form had the highest mortality rate with 76%. The main causes for mortality were sepsis with 62%, cardiovascular disease with 13%, and other causes 18%.