Intestinal strangulation caused by a mucocele of the appendix is extremely rare and difficult to diagnose. It is not usually suspected pre-operatively. This report presents a case of intestinal strangulation due to a mucous containing cystic lesion that was wrapped around the base of a loop of the small bowel. An 89-year-old female was transferred after an acute onset of abdominal pain. A physical examination revealed severe tenderness with guarding in the right upper quadrant. CT of the abdomen showed a loop of dilated small bowel with edema on the right side of the abdominal cavity suggesting a closed loop obstruction. In addition, a low-density thin-walled mass measuring 5 cm in diameter was also seen in the pelvis. Intestinal strangulation was suspected and emergency laparotomy was thus performed. A loop of terminal ileum 25 cm in length was strangulated by a dilated appendix, and ileocecal resection was performed. The resected appendix measured 9 × 3 cm in size and contained mucus. A histopathological examination showed a mucous containing cystic appendix without mucin-producing, neoplastic epithelial cells. A mucocele of the appendix can present in various ways and it is important to recognize this entity at the time of surgery.