Chronic hepatitis C (CHC) increases the risk of liver cirrhosis (LC) and hepatocellular carcinoma (HCC). This nationwide cohort study assessed the effectiveness of viral eradication of CHC. The Taiwanese chronic hepatitis C cohort and Taiwan hepatitis C virus (HCV) registry are nationwide HCV registry cohorts incorporating data from 23 and 53 hospitals in Taiwan, respectively. This study included 27,577 individuals from these cohorts that were given a diagnosis of CHC and with data linked to the Taiwan National Health Insurance Research Database. Patients received either pegylated interferon and ribavirin or direct-acting antiviral agent therapy for > 4weeks for new-onset LC and liver-related events. Among the 27,577 analyzed patients, 25,461 (92.3%) achieved sustained virologic response (SVR). The mean follow-up duration was 51.2 ± 48.4months, totaling 118,567 person-years. In the multivariable Cox proportional hazard analysis, the hazard ratio (HR) for incident HCC was 1.39 (95% confidence interval [CI]: 1.00-1.95, p = 0.052) among noncirrhotic patients without SVR compared with those with SVR and 1.82 (95% CI 1.34-2.48) among cirrhotic patients without SVR. The HR for liver-related events, including HCC and decompensated LC, was 1.70 (95% CI 1.30-2.24) among cirrhotic patients without SVR. Patients with SVR had a lower 10-year cumulative incidence of new-onset HCC than those without SVR did (21.7 vs. 38.7% in patients with LC, p < 0.001; 6.0 vs. 18.4% in patients without LC, p < 0.001). HCV eradication reduced the incidence of HCC in patients with and without LC and reduced the incidence of liver-related events in patients with LC.