To improve the exposure of the left retroperitoneum, a peritoneal incision is made in the left paracolic gutter up to the splenic flexure. By elevating and medially displacing the left colon, the avascular plane between this and the prerenal fascia is entered and developed caudally to the aorta bifurcation, and cranially 3-4 cm beyond the left renal pedicle. Thus, the left kidney, its pedicle, the ureter, the ovarian vessels, and the aorta are adequately exposed. In 81 patients with gynecologic tumors who underwent the modified lymphadenectomy, the median number of aortic nodes removed was 29 (range 21-56). The median duration of left dissection was 35 minutes (range 25-50) and of the entire aortic lymphadenectomy 70 minutes (range 50-120). No major intraoperative injuries occurred. The frequency and type of postoperative complications were not affected by this modification. This new approach provides better exposure of the left retroperitoneum, thus permitting safe and complete dissection of the nodes left of the aorta without increased morbidity. If aortic dissection can be limited to the left side, this technique makes it possible to avoid opening the right retroperitoneum.