BACKGROUND/AIMS Chronic hepatitis B has a high prevalence (>8%) in China. We compared the safety and efficacy of entecavir with that of lamivudine for the treatment of patients with chronic hepatitis B in China. METHODS A total of 519 nucleoside-naive Chinese patients with chronic hepatitis B were randomized (1:1) and treated with entecavir 0.5 mg/d or lamivudine 100 mg/d. The primary endpoint was serum HBV DNA <0.7 MEq/ml by bDNA assay and alanine aminotransferase <1.25 x upper limit of normal (ULN) at week 48. Patients with missing week 48 measurements were considered non-responders. RESULTS About 90% (231/258) of entecavir-treated versus 67% (174/261) of lamivudine-treated patients achieved the primary endpoint (P < 0.0001). The mean reduction from baseline in HBV DNA was greater with entecavir than lamivudine (5.90 vs. 4.33 log(10) copies/ml, P < 0.0001). Greater proportions of entecavir-treated patients achieved undetectable HBV DNA (<300 copies/ml) by polymerase chain reaction assay (76% vs. 43%, P < 0.0001) and alanine aminotransferase normalization (</=1 x ULN, 90% vs. 78%, P = 0.0003). Entecavir and lamivudine achieved comparable rates of HBeAg seroconversion (15% and 18%, respectively). Safety was comparable between the two treatments. CONCLUSIONS For nucleoside-naïve Chinese patients with chronic hepatitis B, entecavir achieves superior virological and biochemical benefit over lamivudine, with a comparable safety profile.