Diverticular disease of the colon is a common disease, and its incidence is increasing gradually. A giant colonic diverticulum (GCD) is a rare entity and is defined as a diverticulum greater than 4 cm in size. It mainly arises from the sigmoid colon, and possible etiology is a ball-valve mechanism permitting progressive enlargement. A plain abdominal X-ray can be helpful to make a diagnosis initially, and a barium enema and abdominal computed tomography may confirm the diagnosis. Surgical intervention is a definite treatment for a GCD. We report a case of an ascending GCD presenting with intussusception in a young adult.