Serum samples were collected at the time of hospitalization from 221 black Africans suffering from cirrhosis and 453 suffering from hepatocellular carcinoma (HCC). These patients came from Senegal, Burundi and Mali, and 6655 adults from different population groups in these countries were used as controls. Hepatitis B virus (HBV) serum markers, including hepatitis B surface antigen (HBsAg), anti-HBs, antibody to hepatitis B core antigen (anti-HBc), HBeAg and anti-HBe, were determined by radioimmunoassay, while alpha-fetoprotein and complexes between HBsAg and IgM were detected by ELISA tests. HBsAg was detected in 11.8-17.6% of controls as opposed to 63.3% of patients suffering from cirrhosis and 62.7% of patients suffering from HCC. There was less evidence for HBV replication in cirrhosis and HCC in older patients. A significant increase in the frequency of HBsAg/IgM complexes was found in passing from the HBsAg chronic carrier state (13.9%) to cirrhosis (29.9%) and finally to HCC (33.7%).