A 74-year-old man presented at our hospital with complaints of abdominal pain, nausea, and vomiting. He had undergone laparoscopic radical cystectomy and ileal conduit for urinary bladder cancer 1 month earlier. The patient had abdominal distention, resonant sounds on percussion, and diffuse abdominal tenderness without rebound or guarding. Abdominal CT revealed dilated jejunal loops herniated through a cord-like structure. Based on these findings, emergency surgery was performed, and intestinal dilatation into the space between the ureter, the ileal conduit, and the sacral bone was detected. The loops were released manually and were not resected. To the best of our knowledge, this is the first case report of small bowel obstruction due to internal hernia caused by the ureter after laparoscopic radical cystectomy and ileal conduit. Retroperitonealization and the minimum required mobilization of the ureters may be necessary when urinary diversion is constructed, especially in laparoscopic or robotic surgeries.