Bone metastasis of hepatocellular carcinoma appears to be peculiar when clinical manifestation of liver disease is not apparent, and initial diagnosis of metastatic hepatocellular carcinoma by fine needle aspiration cytology is rarely obtained. We experienced a case of 45-year-old man with metastatic hepatocellular carcinoma in the sacrum, which was diagnosed by fine needle aspiration cytology. The intrahepatic mass, measuring 1.2 cm in diameter and kept unchanged in size for two years, was never proved to be hepatocellular carcinoma histopathologically. The aspirated neoplastic cells were mostly in sheets, showing abundant acidophilic cytoplasm and large, round, centrally located nuclei with single, prominent acidophilic mucleoli. In the cell block section, diagnosis of metastatic well-differentiated hepatocellular carcinoma was made without difficulty, and definite trabecular fashion with sinusoidal endothelial cell lining was found.