The study was based on the biopsy material collected in Eastern coastal region of South Africa with high incidence of primary hepatocellular carcinoma (HCC). Forty-one patients were between 9 and 25 years old of the total number of 474 cases of HCC available for examination. Liver biopsies were fixed in 10% of neutralised formalin, processed to paraffin blocks, cut and stained with hematoxylin and eosin, silver reticulin, Masson trichrome and Prussian blue stains. Representative biopsies of 21 patients younger than 25 years and 56 older than 35 years were in addition examined immunohistochemically with HBsAg antibody, endothelial marker (F VIII-related antigen) and for oncoproteins c-myc and c-erbB-2 using peroxidase-antiperoxidase method. Cirrhotic liver was evident in 41.5% of all patients and in 28% of younger than 25 years. Hemosiderosis of the liver of patients over 35 years was nearly twice as common as in younger than 25 years and showed the opposite relationship to the presence of HBsAg in liver tissue. Oncoprotein expression was also higher in tumor tissue of younger patients. These results indicate the etiological association of HCC with HBV infection, cirrhosis and possibly siderosis of the liver with HCC. Simultaneous expression of oncoproteins and HBsAg indicate the primary importance of viral infection in etiopathogenesis of HCC.