Meckel's diverticulum is an embryomorphorous vitelline intestine and represents about 1-2% of all autopsy cases. It is said that about 8-22% of all people having the diverticulum manifest some symptoms, and it commonly occurs in children, 80-90% of them, and rarely in adults. Recently we experienced a case of volvulus of Meckel's diverticulum in an adult. A 29-year-old man was seen at the hospital because of abdominal pain, and was admitted for close examination and treatment. On the second hospital day peritoneal sign appeared, and an emergency operation was carried out with a diagnosis of peritonitis. Upon laparotomy, there was a volvulus of Meckel's diverticulum in the ileum about 60cm oral side from the ileocecal region causing necrosis of the diverticulum. So a resection of the verticulum and abdominal drainage were performed. Postoperative course was uneventful. The patient was discharged from the hospital on the 15th hospital day.