Adult intussusception is clinically rare. We report a case with colon intussusception caused by a pedunculated polyp of the sigmoid colon in a 54-year-old male. Abdominal ultrasonographic screening for hematochezia showed intussusception in the sigmoid colon, demonstrating a multiple concentric ring sign and a mobile leading colon polyp. Histological examination of a biopsy specimen of the polyp revealed adenoma. This report suggests that ultrasound imaging is a modality of choice for differential diagnosis of intestinal intussusception with hematochezia in adults.