Peritoneal encapsulation and abdominal cocoon are rare entities, with only 7 and 13 cases, respectively, having so far been reported. A case of each of these conditions is emphasized. Peritoneal encapsulation is probably a development abnormality, largely asymptomatic, and found incidentally at laparotomy or autopsy. The accessory membrane present in front of the small bowel can be easily removed, but excision may not be necessary. Abdominal cocoon is a total or partial encapsulation of the small bowel. It has a tropical or subtropical distribution and presents in young girls as acute or chronic bowel obstruction. Complete recovery is the rule after removal of the membrane. The first example of preoperative radiologic diagnosis is presented. An infective etiology is suggested.