Fusobacterium is a very rare cause of liver abscess. Fusobacteria are anaerobic gram- negative bacilli that are part of normal flora of the oral cavity, the urogenital tract, and the gastrointestinal tract. However, Fusobacterium bacteremia is uncommon, accounting for less than 1% of all bacteremias in adults. Liver abscess due to Fusobacterium nucleatum (F. nucleatum) was reported in patients with AIDS or idiopathic CD4+T lymphocytopenia. We experienced a 54-year-old woman who presented with intermittent fever and generalized weakness for 2 months. Abdominal CT scan revealed an 8 × 10 cm mass in the right hepatic lobe with central low density. Ultrasound-guided aspiration of liver abscess was performed. About 30 mL of greenish-yellow foul-odored pus was aspirated. F. nucleatum was cultured from the aspirated pus. Intravenous administration of antibiotics for 4 weeks and repeated aspiration improved symptoms and decreased size of liver abscess. We report a case of liver abscess due to F. nucleatum in an immunocompetent woman. ( Korean J Gastroenterol 2002; 39: 386-389)