Abstract: Abstract:Objective To elucidate the risk factors in the development clustering of hepatocellular carcinoma in the two families in the area with high mortality of hepatocellular carcinoma in the minority of Yaos in Guangxi region. Methods The two families with clustering of hepatocellular carcinoma were from two different areas with high mortality of hepatocellular carcinoma in the minority of Yaos. Marks of HBV and HCV in sera were tested with ELISA.The HBVDNA and HCVRNA were measured with PCR and RT-PCR, respcetively. The data were analysed by combing with epidemiology survey. Results The positive rates of HBsAg, HBsAb, HBeAg, HBeAb, HBcAb, HBVDNA, anti-HCV and HCVRNA in the two families were 45.0%(9/20), 35.0%(7/20), 15.0%(3/20), 25.0%(5/20), 45.0%(9/20), 25.0% (5/20), 0.0%(0/20) and 0.0%(0/20) and 9.52%(2/21), 42.9%(9/21), 4.8%(1/21), 4.8%(1/21) 23.8%(5/21), 9.52%(2/21), 0.0%(0/21) and 0.0%(0/21) respectively. There was significant difference between the two families in the positive rate of HBsAg (P＝0.01). No significant difference was observed between two families in the positive rate of the other hepatitis virus serological marks. Familiy A used mountain water as the living water, while familiy B used pond water as the living water ten years before. Conclusion There might be a little difference of the risk factors for causation clustering of hepatocellular carcinoma in different area and in different family members. Infection of hepatitis B virus and pond water drinking interacted with the genetic factors,which could be the causation for the clustering of hepatocellular carcinoma.