Abstract: Objective:To observe antiviral efficacy of adefovir on chronic hepatitis B.Methods:Thirty-four cases of patients with chronic hepatitis B were administered oral dose of 10 mg of adefovir once daily.HBVDNA,hepatic function and the serum HBV markers were detected every three months.Results:After 12 months' treatment,HBVDNA converted to negative in 17 cases (50%).Among them,the HBVDNA negative conversion rate in patients whose HBVDNA was less than 10⁷ cop/ml was 66.6%,and it was 23% in patients whose HBVDNA was ≥ 10⁷ cop/ml.There was significant difference between these two kinds of patients (P<0.05).The HBVDNA negative conversion rate in patients whose ALT was less than two folds of normal value was 20%,and it was 71.4% in patients whose ALT was more than two folds of normal value.There was also significant difference between these two kinds of patients (P<0.05).There no correlation between HBVDNA negatives conversion rate and the mode of hepatitis B serum markers (P>0.05).Conclusions:Adefovir is effective in HBVDNA negative conversion rate for the patients with low HBV load and high ALT levels.