The increasing use of laparoscopy as a therapeutic method mandates a reappraisal of the risks involved. Complications frequently described include injuries to the large and small bowels, bladder, and blood vessels. The world literature reports only eight cases of ureteral injury at laparoscopy. In this report, we present five additional cases of ureteral injury occurring at laparoscopy, in addition to a summary of those previously reported. Patients tend to present in the early postoperative period (48-72 hours) with low back pain, abdominal pain, leukocytosis, and peritonitis. The diagnosis should be made by intravenous pyelography; if possible, the injury should be stented by either the retrograde or percutaneous route. The injuries, except for one apparent trocar injury, involved the use of electrocoagulation, both unipolar and bipolar. The injuries occurred most commonly near the uterosacral ligaments. In 38% (five of 13) of the cases, the laparoscopy was performed for treatment of endometriosis. Three of the 13 patients eventually lost renal function of the affected side; two of these underwent a nephrectomy. Because visualization of the ureter near the cervix at the time of laparoscopy is difficult, especially in the presence of disease, laparoscopic procedures in this area must be carried out with caution.