In order to investigate the expression of mutant p53 protein (Mp53) and HBxAg in chronic active hepatitis (CH) and hepatocellular carcinoma (HCC), 30 specimens of HCC with surrounding liver tissues (SL), 15 biopsy specimens from CH were examined with immunohistochemical method (ABC system). The results showed, that 13 (43.3%) specimens of HCC and 15 (50%) of SL were positive for MP53 and HBxAg staining; 3 (16.7%) of HCC and 8 (26.7%) of SL were only MP53 positive, being HBxAg staining negative. On the contrary, 4 (13.3%) of HCC and 1 (3%) of SL were negative for MP53 staining and positive for HBxAg staining (P < 0.05, chi 2 test). In 15 specimens of CH, 3 cases were positive for MP53, 2 for HBxAg. The results indicate that there is a correlation between mutant p53 protein and HBxAg, suggesting that the p53 gene mutation may be closely related with HBV infection, and the mutation of p53 gene would be one of hepatocarcinogenesis mechanisms of HBV.