Background:Interferon (IFN)-based therapies could eradicate hepatitis C (HCV) and reduce the risk of hepatocellular carcinoma (HCC). However, HCC could still happen after sustained virological response (SVR). We aimed to develop a simple scoring system to predict the risk of HCC development among HCV patients after antiviral therapies.Methods:From 1999 to 2009, 1879 patients with biopsy-proven HCV infection treated with IFN-based therapies were analyzed.Results:Multivariable analysis showed old age (adjusted HR (aHR)=1.73, 95% CI=1.13–2.65 for aged 60–69 and aHR=2.20, 95% CI=1.43–3.37 for aged ⩾70), Male gender (aHR=1.74, 95% CI=1.26–2.41), platelet count <150 × 109/l (HR=1.91, 95% CI=1.27–2.86), α-fetoprotein ⩾20 ng ml−1 (HR=2.23, 95% CI=1.58–3.14), high fibrotic stage (HR=3.32, 95% CI=2.10–5.22), HCV genotype 1b (HR=1.53, 95% CI=1.10–2.14), and non SVR (HR=2.40, 95% CI=1.70–3.38) were independent risk factors for HCC. Regression coefficients were used to build up a risk score and the accuracy was evaluated by using the area under the receiver operating characteristic curve (AUC). Three groups as low-, intermediate-, and high-risk are classified based on the risk scores. One hundred sixty patients (12.78%) in the derivation and 82 patients (13.08%) in the validation cohort developed HCC with AUC of 79.4%, sensitivity of 84.38%, and specificity of 60.66%. In the validation cohort, the 5-year HCC incidence was 1.81%, 12.92%, and 29.95% in low-, intermediate-, and high-risk groups, with hazard ratios 4.49 in intermediate- and 16.14 in high-risk group respectively. The risk reduction of HCC is greatest in patients with SVR, with a 5-year and 10-year risk reduction of 28.91% and 27.99% respectively.Conclusion:The risk scoring system is accurate in predicting HCC development for HCV patients after antiviral therapies.