AIMS AND OBJECTIVES The study was conducted to determine the role of lamivudine in the treatment of Nigerian patients with chronic HBV infection (CHB). MATERIALS AND METHODS Twenty one Nigerian patients with laboratory, histologic and clinical features of CHB were studied over a period of 30 months for response to a six-month therapy with lamivudine using liver biopsy as gold standard for assessment of response to therapy. RESULTS The mean age of the patients was 32.6±9.3 years and the receipt of injection from chemists (76%) was the most common risk factor for HBV infection among the subjects. About 67% of the patients were asymptomatic while 90.5% had normal liver span. Patients with low serum albumin, raised serum alkaline phosphatase, bilirubin and globulin prior to lamivudine therapy had restoration to normal values after 24 weeks of therapy. There was prolongation of prothrombin time (five patients) and hypokalaemia (one patient) after lamivudine therapy but there were no changes in the HBsAg, anti-HIV and anti-HCV status of all the patients. Although, post therapy liver biopsy was declined by 8 patients and contraindicated in 5 patients, there was 48% reduction in Knodell score of histologic findings in the liver biopsy specimens of 8 patients who had pre- and post-lamivudine therapy liver biopsies. CONCLUSION The findings from this study suggested that six-month therapy with lamivudine is beneficial in treating Nigerian patients with CHB using biochemical markers and liver histology in assessing response to treatment.