Partially or completely invaginated appendix mistaken for a polyp during colonoscopy and leading to intussusception is a rare situation. This paper describes our experience with two cases of appendiceal intussusception. In the first case, there was no underlying ileocecal abnormality, and, in the second case, histologic examination of the resected appendix and cecum revealed widespread foci of angiodysplasia, and this was thought to be the basis for the intussusception. The authors present reviews of the literature concerning clinical features and associated conditions and emphasize that failure to recognize this condition may result in unexpected complications such as consequent peritonitis in case of endoscopic removal.