A man in his 40's presented with vomiting and numbness in the right thigh. Eight months earlier, he had undergone robot-assisted radical cystectomy and pelvic lymphadenectomy for bladder cancer. Computed tomography (CT) revealed a caliber change and a closed loop of the small intestine in the right pelvis, prompting emergency diagnostic laparoscopy. Intraoperative findings showed that the small intestine had herniated into the space between the right obturator nerve and pelvic wall, resulting in strangulated intestinal obstruction. The necrotic small intestine was resected and reconstructed, while preserving the obturator nerve. The hernia orifice was not repaired during the surgery. We encountered a rare case of an internal hernia involving the obturator nerve as the cord. In patients with abdominal distension and thigh symptoms following pelvic lymphadenectomy, internal hernia should be considered. The optimal approach for hernia repair involving the obturator nerve remains undetermined, necessitating a case-by-case approach.