Studies regarding the clinical significance of quantitative hepatitis B core antibody (anti-HBc) in patients with chronic hepatitis B receiving first-line nucleos(t) ide analogues is limited. The aim of this study was to determine the performance of anti-HBc as a predictor for hepatitis B e antigen (HBeAg) seroconversion in HBeAg-positive CHB patients treated with entecavir. This was a retrospective cohort study consisting of 139 Chinese patients enrolled in a multicenter clinical trial treated with entecavir or entecavir maleate for up to 240 weeks. Anti-HBc evaluation was conducted for all the available samples using a newly developed double-sandwich anti-HBc immunoassay. At week 240, 35 (25.2%) patients achieved a serological response (HBeAg seroconversion) and these patients at week 240 had significantly higher levels of anti-HBc (P<.01). We defined 4.65 log(10) IU.mL(-1), with a maximum sum of sensitivity and specificity, as the optimal cut-off value of baseline anti-HBc level to predict seroconversion. Patients with baseline anti-HBc >= 4.65 log(10) IU.mL(-1) had 28.0% (26/93) and 35.5% (33/93) chance of seroconversion at weeks 144 and 240, respectively. The baseline anti-HBc level was the strongest predictor for seroconversion at week 144 (OR: 5.78, 95% confidence interval [CI]: 2.05-16.34, P=.001). The baseline anti-HBc level was a strong predictor for seroconversion at week 240 (OR: 5.36, 95% CI: 2.17-13.25, P<.001). Hence, baseline anti-HBc titre is a useful predictor of long-term entecavir therapy efficacy in HBeAg-positive CHB patients, which could be used to optimize antiviral therapy.