The aim of this study was to elucidate the antiviral efficacy and the predictors of entecavir treatment in nucleoside-naive chronic hepatitis B patients.A total of 160 patients treated with entecavir (0.5 mg daily) for at least 24 weeks were consecutively enrolled. The virologic response (HBV DNA1 log(10) copies/mL increase in HBV DNA level above nadir on two consecutive occasions) were retrospectively analyzed.The mean follow-up duration was 58.8 weeks, and 85 patients (53.1%) showed HBeAg positivity. The median pretreatment levels of serum ALT and HBV DNA were 99 IU/L and 7.6 log(10) copies/mL, respectively. The cumulative rates at 12, 24, 48, and 72 weeks were 37.5%, 68.1%, 87.4%, and 95.8%, respectively, for the virologic response; 40.0%, 66.2%, 84.5%, and 92.7% for the biochemical response; 10.6%, 18.8%, 27.0%, and 34.5% for HBeAg loss; and 3.5%, 7.1%, 9.0%, and 13.2% for HBeAg seroconversion. There was no case of virologic breakthrough. An absence of HBeAg and a low serum HBV DNA level (<8 log(10) copies/mL) at baseline were significant predictors of the virologic response in a multivariate analysis (P<0.01).Entecavir therapy showed excellent efficacy in nucleoside-naive chronic hepatitis B patients. The predictors of a virologic response were an absence of HBeAg and a low baseline HBV DNA level.