A retrospective study of 737 consecutive patients surviving the first 24 hours who underwent valve replacement surgery from July 1980 to June 1993 was undertaken to determine the prevalence, variables that could be used to predict outcome and results of therapy for postoperative acute renal failure[ARF]. Twenty-one patients[2.8 %] developed acute renal failure. Positive risk factors noted in the development of postoperative renal failure included age, New York Heart Association class III & IV, endocarditis and elevated preoperative concentration of serum creatinine. The duration of cardiopulmonary bypass, aortic cross-clamping and the total duration of the operation also closely correlated with the incidence of ARF. The mortality rate for established ARF was 38.1% and ARF was associated with a significant increase in the length of hospitalization, ventilator support and intensive care unit stay. The incidence and mortality rate of oliguric renal failure was 38.1% and 85.7%. The highest mortality rate was associated with two or more postoperative complications and serum creatinine value exceeded 5 mg/dl. We concluded that therapy should be aimed at prevention of oliguric renal failure, or at least its conversion to nonoliguric renal failure, and early institution of renal replacement therapy with intensive support probably gives the best chance for survival.