A case of intussusception of the descending colon caused by a lipoma in a 44-year-old man is reported. He was seen at the hospital because of melena. Colonoscopy revealed a tumor of the descending colon. Computed tomography and ultrasonography of the abdomen revealed intussusception in the descending colon and fat density tumor at the distal end of the intussusception. After reduction of intussusception, a laparotomy was performed. The descending colon was fixed loosely to the retroperitoneum. The descending colon was partially resected and the histopathological diagnosis was lipoma of the submucosal layer of the colon. The postoperative course was uneventful. The patient was discharged from the hospital 14 days after the operation.