Estimated glomerular filtration rate (eGFR) can be readily calculated from serum creatinine values. It is a more sensitive prognostic indicator than serum creatinine alone in patients undergoing thoracoabdominal or endovascular abdominal aortic aneurysm repair. The value of eGFR in patients undergoing open abdominal aortic aneurysm repair remains unclear. The preoperative eGFR was calculated for patients undergoing elective open infrarenal aortic aneurysm repair. Postoperative complications, perioperative mortality, and long-term survival were compared across eGFR and serum creatinine quartiles. The eGFR identified preoperative renal dysfunction in 33% of patients, whereas serum creatinine identified renal impairment in only 11%. The eGFR correlated with perioperative morbidity and long-term survival. Serum creatinine did not correlate with perioperative mortality or long-term survival. However, it did correlate with postoperative morbidity. The eGFR is a more sensitive index of preoperative renal function than serum creatinine and correlates with survival. It should replace serum creatinine as the standard index of renal function before open abdominal aortic aneurysm repair.