A 71-year-old male patient was readmitted to our hospital 1 month after discharge because of relapse of abdominal pain. He had been diagnosed with hepatocellular carcinoma (HCC) 1 year prior and had undergone repeated transcatheter arterial chemoembolization and radiotherapy. During the last hospitalization, he was diagnosed with a liver abscess complicated by previous treatments for HCC and was treated with intravenous antibiotics and abscess aspiration. Follow-up abdominal computed tomography revealed a liver abscess with a duodenal fistula, which was successfully treated with endoscopic Histoacryl injection into the fistula. Liver abscesses with duodenal fistulas rarely occur, but they are intractable and possibly fatal in patients with HCC. In the literature, they have frequently been managed only with abscess treatment without fistula management. We herein report the first case of a patient with a liver abscess complicated by a fistula between the duodenum and the abscess, which was treated with endoscopic Histoacryl injection.