Intussusception in adults is not common unlike in pediatrics. It also differs from the pediatric intussusception in its origins, symptoms, and treatment. Since more than half of intussusception cases come from malignancy, laparotomy is considered to be the treatment of choice in most cases. This report deals with a patient who visited our hospital complaining of abdominal pain after colonoscopic polypectomy. The patient was diagnosed with colonic intussusception. After a conservative treatment regimen including antibiotics and fluid therapy, the intussusception was spontaneously reduced. (Korean J Gastrointest Endosc 2009;39:111-114)