Two cases of cecal volvulus in children with mental disability are described. Case 1: a 3-year-old girl with trisomy 18 was admitted with abdominal pain and vomiting. She had received left lateral segmentectomy 6 months earlier because of hepatoblastoma. Release of the cecal volvulus followed by the fixation of the cecum and ascending colon to the right retroperitonium was performed. Case 2: a 15-month-old boy with Cornelia de Lange syndrome who had undergone a standard Nissen's fundoplication. On the sixth postoperative day, progressive abdominal distention developed. Abdominal color Doppler ultrasonography from the right rear side revealed a clockwise-twisted ileocecal artery and vein and a dilated colon with tapering configuration. On the ninth postoperative day, emergent release of the cecal volvulus followed by ascending colostomy through a perforation site was performed. Approximately 40 children with cecal volvulus have so far been reported, of whom 13 are mentally disabled. We speculated that in the cases reported here, distention of the intestine accompanying the mental disability and the previous surgery contributed to the development of cecal volvulus in addition to the prerequisite of abnormal mobility of the cecum. Pediatric surgeons should consider the cecal volvulus as a cause of intestinal obstruction in mentally disabled children.