Background and Aims:The impact of nonalcoholic fatty liver disease (NAFLD) on the treatment outcome of chronic hepatitis B (CHB) is undefined and deserves an in-depth investigation. Methods: Histologically-proven CHB receiving first-line antiviral regimens as initial therapy was enrolled and grouped by the concurrence of NAFLD, and followed up at six monthly intervals. Therapeutic response related data were recorded and compared at multiple time points. Kaplan-Meier and Cox regression analyses were utilized to estimate the impact of NAFLD on complete virological response (CVR). Results: We enrolled 267 patients (CHB: 164; CHB with NAFLD: 103) with comparable follow-up durations. They were also comparable in baseline HBV DNA levels and HBeAg positivity. Patients with concomitant NAFLD showed less significant decline in HBV DNA, qHBsAg, pgRNA, and liver enzyme levels over time; moreover, their cumulative incidences of CVR were significantly lower and that of low-level viremia (LLV) were significantly higher at 6, 12, 18, 24 months. First CVR of CHB was delayed with the presence NAFLD (11.0 vs. 7.0 months, p<0.001) and further prolonged with higher grade of liver steatosis (Grade 2-3 vs. 1: 13.0 vs. 9.0 months). On multivariate analysis, HBeAg positivity (HR: 0.650, p=0.036), grade of steatosis (G2 [HR: 0.447, p=0.004]; G3 [HR: 0.085, p=0.002]) and HBV DNA (log10 IU/mL) (HR: 0.687, p<0.001) were significantly associated with delayed CVR, whereas grade of necroinflammation (HR: 1. 758, p<0.001) accelerated the CVR. Conclusions: In CHB patients receiving initial antivi-ral therapy, NAFLD was associated with higher levels of HBV DNA, pgRNA, and liver enzymes, and higher incidence of LLV and delayed CVR.