Objective: The objective of this study was to compare the risk of adhesion formation and the site of postoperative adhesions after transperitoneal versus extraperitoneal laparoscopic para-aortic lymphadenectomy. Study Design: A prospective study was conducted on 66 pigs, randomly allocated to 2 groups of 33 animals that underwent transperitoneal versus extraperitoneal laparoscopic para-aortic lymphadenectomy. Results: No statistically significant difference was observed between the 2 techniques in terms of operating time, number of lymph nodes removed, and intraoperative and postoperative morbidity. More lymphoceles were observed in the extraperitoneal laparoscopy group (P =.0002). The overall adhesion rates were 76% in the transperitoneal group and 43.33% in the extraperitoneal group (P =.04). The adhesion score specific to the operative site was lower in the extraperitoneal group (P =.0005). A stereolocalization study showed that almost all adhesions after transperitoneal laparoscopy were situated in the para-aortic external irradiation field, whereas adhesions after extraperitoneal laparoscopy were predominantly situated outside this field. Conclusion: Extraperitoneal laparoscopy generates significantly fewer adhesions in the para-aortic irradiation field. (Am J Obstet Gynecol 2000;183:529-33.)