For decades, lumbar discectomy has been one of the most common surgical practices performed by neurosurgeons. Although it has proved to be an effective and safe surgical procedure, life threatening complications may occur in rare cases, including iliac artery and/or vein injuries, superior rectal artery injury, common iliac artery aneurysms, iliac arteriovenous fistula, intestinal injuries, and ureteral injuries. Ureteral damage during the lumbar L4-5 microdiscectomy was reported in a slim 50 year-old male patient. Because of a small amount of bleeding occurred during the surgery as soon as the patient came out of anesthesia, an angio-computed tomography (CT) of the abdomen was performed. It showed no hematoma and no major vascular injury, but air bubbles were seen in the retroperitoneal region, indicating that perforation had occurred. The patient was then monitored carefully for immediate and possible subsequent injuries, in this way; ureteral damage was found and repaired. This is perhaps the first such case report in the literature of the early detection of ureteral damage using an angio CT scan. If there is a suspicion of perforation of the anterior annulus fibrosus and anterior longitudinal ligaments but no indication for an emergency laparotomy, an abdominal angio CT done immediately after the surgery and an abdominal non-contrast CT 4 hours later will give sufficient information concerning the potential occurrence of nearly all the major complications associated with lumbar discectomy.