We describe a case of hemorrhage from the colon diverticulum successfully treated by transcatheter arterial embolization. A 64-year-old man, who had been diagnosed with diabetes mellitus but not treated, was seen at our hospital on January 24, 1998 because of anal bleeding. Emergent colonoscopy revealed multiple diverticula at the cecum and ascending colon, one of which was the bleeding point. We tried to stop the bleeding at that time, but failed. Considering the poor risk for laparotomy, we performed a transcatheter arterial embolization. We embolized a marginal artery over about 4cm by two coils and achieved hemostasis. In conclusion, the technique of a transcatheter arterial embolization is effective for diverticular bleeding especially in the case of a high risk patient.