BACKGROUND A recommendation was made by the ACT-HBV Asia-Pacific Steering Committee regarding the withdrawal of lamivudine in chronic hepatitis B patients after achieving effective maintained virological suppression. The outcome of patients following this therapeutic guideline has not been clearly investigated. OBJECTIVE In this study, we examined the outcome of patients adherent to the lamivudine withdrawal guideline. METHODS Seventy-one chronic hepatitis B patients achieving seroconversion of hepatitis B e antigen (HBeAg) as well as effective maintained virological suppression during lamivudine therapy were included. Lamivudine was withdrawn provided that undetectable HBV-DNA had been documented on two separate occasions at least 6 months apart. The patients were followed for a median period of 15 months (range, 6-72 months). The effect of pre-therapeutic clinical and virological factors on time to relapse was analyzed. RESULTS Of the 71 patients, 19 (27%) relapsed, of whom 5 showed reappearance of HBeAg and 14 had HBeAg-negative hepatitis. Cox proportional hazard model showed pre-therapeutic HBV-DNA level was the only predictor for time-to-relapse (hazard ratio=1.023, 95% confidence interval=1.004-1.043, P=0.020). Categorical analysis showed that 15/34 (44.1%) and 4/37 (10.8%) patients with pretreatment HBV-DNA levels >10(8) and <or=10(8)copies/mL, respectively, relapsed during follow-ups. The accumulative relapse rates were significantly different between the two groups of patients (Kaplan-Meier method, P=0.003). CONCLUSIONS In patients with pretreatment HBV-DNA levels <or=10(8)copies/mL, lamivudine could be withdrawn after achieving effective maintained virological suppression. Relapse of HBeAg-negative hepatitis remained a major problem.