The purpose of this study was to determine the effect of preoperative renal failure on the outcome of patients undergoing infrarenal abdominal aortic aneurysm (AAA) repair. Of 251 patients undergoing AAA repair from 1977 to 1984, 10% had evidence of preoperative chronic renal failure. These patients were classified according to their preoperative serum creatinine values; group I had preoperative creatinine levels of 2 to 4 mg/dl, group II had creatinine levels greater than 4 mg/dl but no history of hemodialysis, and group III consisted of patients on chronic hemodialysis before operation. One of 16 patients in group I developed transient high-output renal failure postoperatively. Four of the six patients in group II (67%) developed significant postoperative deterioration of renal function and required acute hemodialysis. Of the four patients in group III maintained on chronic hemodialysis preoperatively, one died of sepsis from an ischemic colon. This experience suggests that patients with mild renal dysfunction (serum creatinine value less than 4 mg/dl) can undergo elective AAA repair without additional morbidity. Patients on hemodialysis before operation can also safely undergo surgical repair of their AAAs electively if dialyzed the day before operation. Patients with severe renal dysfunction (serum creatinine greater than 4 mg/dl) who are not on hemodialysis should be considered for dialysis preoperatively in an attempt to reduce the high incidence of serious postoperative renal functional deterioration and subsequent morbidity.