A 47-year-old man was admitted to our hospital due to upper gastrointestinal bleeding. Endoscopy revealed a large protruding mass with mucosal ulceration and bleeding over the second portion of the duodenum. Abdominal computed tomographic scan revealed a heterogenous tumor extending from the right lobe of the liver and encroaching on the duodenal wall. A diagnosis of metastatic hepatocellular carcinoma of the duodenum was made after an endoscopic biopsy. Partial hepatectomy and Whipple's procedure were performed. The patient's postoperative course was uneventful. Tissue pathology revealed an extensive primary hepatic tumor which had caused an ulcer in the second part of the duodenum and then protruded into the lumen. The patient survived another two years with no recurrence of hepatic lesion or bleeding and died of sepsis after metastasis to the right adrenal gland which was first noted at 18 months postoperatively. The presentation of hepatocellular carcinoma as upper gastrointestinal bleeding following duodenal perforation by the tumor through the bed of a large duodenal ulcer is quite unusual.