Various forms of renal replacement therapies are available to treat acute renal failure (ARF) after cardiac surgery. The objective of this study was to assess the incidence of ARF developing postoperatively necessitating continuous veno-venous hemofiltration (CVVH) in adult patients requiring cardiopulmonary bypass (CPB), to determine the factors which influence the outcome in these patients and to assess the outcome following the use of early and intensive CVVH. During the study period, i.e. August 2000 to July 2002, 2355 adult patients underwent surgery under CPB, of whom 159 (6.7%) developed renal failure (creatinine >200 micromol/l) and 116 (5%) needed CVVH. Patients excluded were those who died within 24 h and those who underwent coronary artery bypass grafting without utilising CPB, thoracoabdominal aneurysm operations and pericardial surgery. Average age, Parsonnet score and Euroscore in the study population were 69.9 years, 21 and 7.70, respectively. Of the 116, 45 died in the intensive care unit (38.8% mortality). Relatively more non-survivors suffered from diabetes and preoperative renal dysfunction (P<0.05). Adverse outcome was also more likely if patient suffered from postoperative cardiac failure or had gastrointestinal complications or had more than two organ systems failing (P<0.05). Mortality was 100% if hepatic failure ensued.