In contrast to the idiopathic cause of intussusception in children, adult intussusception in most patients is associated with organic causes. The majority of these patients are brought to the operating room with the preoperative diagnosis of bowel obstruction, and the surgeon discovers an intussusception intraoperatively. But the increasing use of abdominal CT may improve the ability to diagnose intussusception. There is no universal agreement upon the correct treatment of adult intussusception, although most authors agree that surgical intervention is necessary. In the more recent reports, colonoscopic reduction of intussusception has been reported for selected patients. For patients in whom the involved ileum is extremely long, it is advisable to attempt an operative reduction or colonoscopic reduction selectively. Thus, we report here on two patients with benign and malignant lesion, respectively, that caused ileocolic intussusception; preoperative colonoscopic diagnosis and reduction were attempted for these patients, although the patients were not reduced by colonoscopic procedure.