Uterine broad ligament hernia is a rare type of internal hernia, with symptoms similar to those of adnexal torsion. Distinguishing these disorders is crucial. We treated a 49-year-old Japanese woman with a history of gravida (n=5), parity (n=3), and cesarean sections (n=2). After visiting a physician due to abdominal pain and vomiting, she was referred to our hospital based on suspicion of ovarian torsion. Emergency surgery at our hospital revealed that the patient's small intestine was contained within the defective hilar membrane, resulting in a uterine broad ligament hernia. With the cooperation of the intestinal surgeon, we performed a resection and anastomosis of the necrotic small intestine in the herniated area. The patient's postoperative course was uneventful, and she was discharged on the 9th postoperative day. A uterine broad ligament hernia causes necrosis of the small intestine and can be life-threatening. Women with a history of surgery or delivery might be at higher risk for this hernia. The swollen small intestine at the hernia site is often mistakenly diagnosed as adnexal torsion. In this patient's case, we diagnosed the uterine broad ligament hernia with necrotic small intestine during the surgery. The prompt surgery enabled a good patient prognosis.