The case is reported of incarcerated intestinal hernia in a hernia sac of reversed ileal conduit wall protruding through the stoma. An 82-year-old woman presented with suspected parastomal intestinal hernia. The patient had undergone total cystectomy with ileal conduit construction 3 years previously, followed by stomal reconstruction surgery for stomal stenosis 2 years later. She had been taking various kinds of purgatives for severe constipation. Initially, this case was diagnosed as parastomal hernia, but emergency surgery demonstrated that incarcerated intestinal hernia in a hernia sac of reversed ileal conduit wall was protruding through the stoma. This case was apparently caused by high abdominal pressure and thinning of the ileal conduit wall.