<正> The in situ hybridization of HBV DNA with biotinylated probe informalin-fixed and paraffin-embedded liver tissue sections was performed and thelocalization and morphology of HBV DNA in various types of chronic liver diseases wereobserved.25 out of the 75 cases studied were HBV DNA positive （33.3%）.HBV DNA inhepatocytes was demonstrated as numerous coarse grains in cytoplasm and occasionally afew grains in individual nuclei.The distribution of the HBV DNA positive hepatocytes inthe sections was in 3 types

i.e.

the diffuse type （Type I

4/25

16%）

the focal type （Type Ⅱ

20/25

80%）

and the scattered type （Type Ⅲ

1/25

4%）.The HBV DNA grains incytoplasm might be condensed （Type a） or sparsed （Type b） depending on the number of theHBV DNA grains.The different distribution patterns and the amount of HBV DNAgrains might be a reflection of the replication activity and the state of infectivity of HBV.HBV DNA positive hepatocytes were found only in the tissues contiguous to the cancertissue in cases with hepatocellular carcinoma with cirrhosis.