Adhesion re-formation after a reproductive operation, particularly involving the pelvic sidewall, is a prominent cause of failure in the surgical treatment of infertility. This study was done to evaluate the impact of standard microsurgery through laparotomy and the additional benefit of an oxidized regenerated cellulose adhesion barrier (INTERCEED® [TC7] Absorbable Adhesion Barrier [Ethicon Inc.]), in reducing pelvic sidewall adhesion re- formation. One hundred and thirty-four patients with bilateral pelvic sidewall adhesions undergoing adhesiolysis by standard microsurgical techniques through laparotomy were treated during a prospective randomized trial involving 13 centers. After adhesiolysis, the deperitonealized surface of one pelvic sidewall was randomly assigned to be covered with INTERCEED Barrier, the contralateral sidewall serving as control. A second-look laparoscopy was performed ten days to 14 weeks postoperatively. Microsurgical adhesiolysis alone resulted in 24 percent of the sidewalls becoming free of adhesions and a 55.6 percent reduction in the area of adherent peritoneum. With microsurgery alone, 60 and 39 percent of adhesions initially characterized as filmy or severe, respectively, were not seen at second-look laparoscopy. The use of INTERCEED Barrier increased the incidence of adhesion-free sidewalls twofold. The treatment was also associated with a statistically significant reduction in the area of peritoneum affected by adhesion re-formation, compared with the control wall. Of the adhesions originally graded as severe, 61 percent of those treated with INTERCEED Barrier did not re-form at all. When evaluated on filmy adhesions, the use of the barrier was associated with a 72 percent reduction in adhesion re- formation. A measurable reduction in adhesion re-formation was found, depending on the initial adhesion type, with microsurgery alone. The addition of INTERCEED Barrier further reduced the incidence, extent and severity of postoperative adhesion re-formation. In this study, 90 percent of the patients benefited from the use of INTERCEED Barrier.