We analyzed 432 patients with acute tubular necrosis, dialyzed at the University of Minnesota Dialysis Unit between 1968-1979. Only 135 patients or 31% survived. The median time to death was 5 days and to recovery of renal function was 12 days. Serum creatinine continued to fall for one month after the last dialysis and then stabilized. Ultimate serum creatinine level was directly related to age of patient but not duration of need for dialysis. One-fourth of the patients were left with moderate renal insufficiency (creatinine 1.5-3 mg/dl). Eight of 82 (10%) of the patients with long term (greater than 1 mo follow-up) had severe renal failure (creatinine over 3 mg/dl) and 4 other patients never recovered renal function but needed chronic hemodialysis. Acute renal failure is numerically important but not very time demanding on the capacity of dialysis units. The majority of the patients have no clinical problem of renal dysfunction if they survive their basic disease leading to acute tubular necrosis.