Severe acute renal failure associated with surgical diseuse and a highly catabolic state poses a major therapeutic challenge. Treatment by conventional dialysis or arteriovenous hemofiltration suffers from serious shortcomings. The current study assesses the clinical and biochemical impact of a newer approach (continuous hemodiafiltration) in a cohort of 60 critically ill surgical patients with severe renal failure. All patients were studied prospectively and assessed for illness severity. Their biochemical response to therapy was analyzed and their clinical course to either death or hospital discharge documented. The use of continuous hemodiafiltration (CHD) permitted full control of azotemia in all patients (mean steady-state urea concentration: 19.8 mmoil/L) and was associated with rapid control of acidemia (mean pretreatment pH: 7.27; mean ph after 24-h treatment: 7.35; p < 001). During the 15,696 h of therapy, there were no treatment-induced episodes of hypotension and/or hyporemia. All patients were able to receive full-dose enteral (9) or parenteral (51) nutritional support with 1.5 to 2.5 g/kg/day of protein as tolerated. Despite their illness severity.