Treatment of chronic hepatitis B in renal transplant recipients remains one of the major problems in clinical nephrology. Lamivudine is considered to be a drug of choice for these patients, however, its efficacy in patients with hepatitis B after renal transplantation (RT) has not been completely proven. Twenty-two RT recipients treated with lamivudine were evaluated. The duration of treatment was 15.6+/-1.9 months. Fourteen patients (64%) had normalization of aminotransferase (ALT); in 9 of them (41% of the whole group), serum HBV DNA was eliminated. Serum HBeAg was undetectable in 4 out of 15 (27%) previously positive patients. It has been statistically proven that the efficacy of lamivudine therapy correlates with degree of fibrosis and higher histological activity index values. We could not establish any correlation between the outcome of antiviral therapy and patients' age, sex, conditions of contagion (while on dialysis or after RT), time lapsed after the infection had been detected, duration of post-transplant period, type of immunosuppression, HBeAg positivity or negativity, ALT levels, concomitant HCV infection. The efficacy of antiviral HBV therapy is limited by the duration of lamivudine treatment: in 4 out of 5 patients with virologic response, the viremia condition relapsed several weeks after the medication had been stopped. Two patients continued to sustain their biochemical response and 1 patient had ALT levels elevated to above normal, but the value was almost twice as low as initially reported. Liver biopsy was repeated in 4 RT recipients after the end of antiviral therapy; in 3 of them positive morphologic changes were observed.