We investigated the incidence and endoscopic features of gastroduodenal lesions which appeared after transcatheter arterial chemo-embolization (TACE), performed 29 times in 25 patients with inoperative hepatocellular carcinoma. The new development or exacerbation of the gastroduodenal lesions after TACE was evident in 13 of the 29 (45%). The side of the lesions ranged from the gastric body to the second portion of the duodenum, and the lesions that developed were multiple ulcers in four, and multiple erosions with white coat in nine. The development of these gastroduodenal lesions may be due to mucosal ischemia caused by embolic materials, the toxic effect of antineoplastic drugs infuse, or to stress. In light of these events, upper gastrointestinal endoscopy should be added to the usual examinations done for patients undergoing TACE.