Ten women had endometriosis and pelvic peritoneal defects of the posterior leaf of the broad ligament, with the consistent finding of medial displacement of the ureter toward the uterosacral ligament. Ureterolysis at the time of surgery revealed the underlying course of the ureter and its proximity to the uterosacral ligament, making it susceptible to surgical injury. It is important for surgeons to be aware of this anatomic alteration associated with these specific peritoneal defects.