A preoperative obliteration of the renal vascular bed was performed in 90 patients by Gelfoam emboli. This procedure facilitates the ligation of the renal vein and artery during transabdominal nephrectomy. The decreased vascularity lessens the risk of tumor embolization and reduces the duration of the surgical procedure by half. A simple routine percutaneous method of occlusion is described. Gelfoam emboli are unsuited for permanent obliteration in bleeding tumors.