The familial environment may also play an important role in the epidemiology of HCV infection through vertical and horizontal transmission by infected household members. However, it is still controversial whether familial clustering of HCV occurs. We experienced a case of familial clustering of hepatitis C virus. A 10-year old girl presented with nausea, vomiting and anorexia for a month was diagnosed as hepatitis C. Her mother, grandmother, a maternal aunt and her daughter had contracted with HCV. Her laboratory findings showed AST/ALT 63/122 IU/L, positive anti-HCV Ab and HCV RNA (3.54 × 10⁵ copies/mL). Pathologic findings of the liver biopsy revealed chronic hepatitis with minimal lobular activity, mild porto-periportal activity and mild portal fibrosis. After treatment with interferon-α 2b for 6 months, the clinical symptoms and laboratory findings were normalized.