Internal hernias through broad ligament defects are very rare and difficult to diagnose preoperatively. We report the case of a 92-year-old woman who was admitted to our hospital for abdominal pain. The contrast-enhanced multi-detector CT (MDCT) showed a dilated small intestine in the left lower abdomen. The proximal and distal transition point of the small intestine was adjacent to the left broad ligament. The uterus was compressed right ventrally. The penetration of the small intestine through the left broad ligament from ventral to dorsal was also visualized. From these findings, an internal broad ligament hernia with incarcerated bowel was suspected. Despite our strong recommendation several times of an exploratory laparotomy, the patient flatly refused surgery because of her advanced age. We thus unwillingly chose conservative treatment with the transnasal placement of a drainage catheter. The following morning, she consented to surgery due to worsening abdominal pain and underwent a laparotomy 33 hr after onset. A 120-cm long loop of small bowel had herniated through a defect in the left broad ligament. This necrotic segment of bowel was resected and end-to-end anastomosis was performed. The defect in the broad ligament was closed to avoid recurrence. The postoperative course was unremarkable. MDCT is useful in the preoperative diagnosis of this disease.