Patients dually infected with hepatitis C virus (HCV)/hepatitis B virus (HBV) have a higher risk of developing advanced liver disease or hepatocellular carcinoma compared with monoinfected patients. Yet, there is a similar rate of sustained virologic response (SVR) after peginterferon alfa-2a and ribavirin combination therapy in these patients compared with HCV-monoinfected patients and a high hepatitis B surface antigen (HBsAg) seroclearance rate. The durability of hepatitis C and B clearance in coinfected patients was investigated in a 5-year follow-up study. Patients with active HCV genotype 1, both HBV-coinfected (n = 97) and HBV-monoinfected (n = 110), underwent 48-week combination therapy with peginterferon alfa-2a plus ribavirin. In patients with active HCV genotype 2 or 3, both HBV-coinfected (n = 64) and monoinfected (n = 50) patients underwent 24-week combination therapy. A total of 295 (91.9%) patients completed treatment and 24 weeks posttreatment follow-up; 264 (89.5%) patients agreed to receive additional follow-up for up to 5 years after the end of treatment. After a median follow-up of 4.6 ± 1.0 years, six of the 232 patients achieving SVR developed HCV RNA reappearance, including five HCV genotype 1/HBV-coinfected patients and one HCV genotype 2/3-monoinfected patient. Subgenomic analysis of the HCV core gene indicated that five patients developed delayed recurrence of HCV infection. Overall, the cumulative recurrence rate of HCV infection was 2.3% (0.4%/year; 95% confidence interval [CI], 0.9%-5.5%). The cumulative HBsAg seroclearance rate was 30.0% (95% CI, 21.5%-42.0%); with 33.1% (95% CI, 21.8%-50.1%) in the 48-week combination therapy group and 24.3% (95% CI, 13.7%-42.9%) in the 24-week therapy group. Conclusion: Peginterferon alfa-2a and ribavirin therapy provides good HCV SVR durability and a high accumulative HBsAg seroclearance rate in patients who are coinfected with HCV and HBV. (HEPATOLOGY 2013;)