Acute renal failure continues to be a common occurrence in critically ill cancer patients. It frequently results from a combination of risk factors, which include the following: hemodynamic alterations associated with renal ischemia; exposure to nephrotoxic drugs; urinary tract obstruction; and specific abnormalities related to cancer itself. Recent advances in the techniques of hemodialysis, nutritional support, and the recent introduction of continuous arteriovenous hemofiltration have improved the care of these patients.