The efficacy and safety of recombinant interferon alfa-2a (rIFN) was evaluated in 26 adult Nigerian patients with chronic hepatitis B infection. Male and female patients with serological evidence of HBV infection (HBsAg and/or HBeAg positive patients) and abnormal liver histology were monitored for six months to confirm chronicity. At the end of the six months screening period eligible patient were enrolled into the study and treated with rIFN 4.5 MIU given three times a week for 6 months. Efficacy was assessed primarily by loss of HBV-DNA and/or HBeAg from serum and secondarily by loss of HBsAg and normalization of the liver histology. Safety was assessed by monitoring the leukocyte and platelet count over the treatment period whilst tolerability was assessed by recording the occurrence of adverse events (adverse drug reaction and intercurrent illness). At the end of therapy the response rate with respect to loss of HBV-DNA was 67% and 100% for HBeAg (i.e. for the six patients who were HBeAg positive at baseline). There was loss of HBsAg in 22.2% of the patients. A significant reduction in inflammation and necrosis scores was found among the 10 patients who had both baseline and term biopsies. The frequency of occurrence of adverse events was 53.8% and the laboratory safety parameters were not significantly affected by therapy (p > 0.05). 19.2% of the enrolled patients were withdrawn from the study prematurely. These results demonstrate that rIFN is effective in the management of CHB infection even in Nigerians. The high success rate associated with HBcAg clearance is particularly noteworthy.