In 12, 505 patients who received barium enemas during the past 14 days, 979 cases (7.8%) of diverticular disease of the colon (DDC) were found. The incidence of DDCincreased with age; 2.2% of the patients were below age 29 and 14.3% were over 70 years old. The sex distribution was 584 males and 395 females. 76.1% had diverticula in the right-side colon, 12.9% in the left-side colon, and ll.0% in both sides. All patients below age 29 had the right-side colon type, while 44% of those aged 70 or moredid. On the other hand, the left-side colon type and both-sides colon type were found only in patients over 30 years old, and constituted a majority in those of 70 years old or more. The main symptoms and signs were: disturbances in bowel habits 50.7%, abdominal pain 48.1%, abdominal distension and/or discomfort 41.5%, occult blood 25.2% and melena 5.8%. Therefore, DDCis clinically becoming an important disease in recent years in Japan as well as in Western countries.