We determined the risk of arteriovenous fistula after en bloc ligation of the renal hilum.A prospective evaluation of all patients who underwent en bloc ligation of the renal hilum during nephrectomy for malignant disease was performed. Pertinent operative data were recorded and patients were followed for clinical evidence of arteriovenous fistula formation, including hypertension, abdominal bruit and new onset congestive heart failure. Patients with at least 12 months of followup underwent computerized tomographic arteriography to assess arteriovenous fistula formation.A total of 94 patients underwent en bloc renal hilar ligation during open (43) and laparoscopic (51) nephrectomy using a 45 mm titanium endovascular stapler. Of this cohort 11 patients were lost to followup and 3 died of disease. The remaining 80 patients were followed an average of 35.2 months with no clinical evidence of arteriovenous fistula formation. Specifically there was no statistically significant difference in preoperative and postoperative blood pressure (p = 0.18 and 0.62, respectively), no evidence of abdominal bruit on examination and no new onset congestive heart failure. A total of 32 had increased serum creatinine and, therefore, they were excluded from followup computerized tomographic arteriography. Eight patients had a followup of less than 1 year and they were not yet eligible for evaluation. In the 40 patients who underwent computerized tomographic arteriography no fistulas were noted.Based on clinical followup and prospective radiographic evaluation there appears to be a low risk of arteriovenous fistula formation after en bloc ligation of the renal hilum using a titanium endovascular stapler.