Eleven adult patients with intussusceptiqn observed during 1979 to 1994 were reported. Adult intussusception is uncommon. It may be categorized into four groups: 1. tumor-related (seven cases); 2. postoperative (two cases); 3. miscellaneous-Meckel's diverticulum (one case); and 4. idiopathic (one case). Tumor-related intussusceptions were caused by benign tumors in six patients and by malignant tumor in one. Postoperative causes were related to various factors including gastrojejunal anastomosis and multiple adhesions. Miscellaneous factor was due to Meckel's diverticulum. The idiopathic intussusception had no demonstrable organic lesion. Treatment of adult intussusception must be surgical, using resection without reduction.