AIM: To assess whether a 24-wk course of interferon (IFN) could prevent hepatocellular carcinoma (HCC) recurrence and worsening of liver function in patients with hepatitis C virus (HCV)-infected patients after receiving curative treatment for primary HCC. METHODS: Outcomes in 42 patients with HCV infection treated with IFN-α, after curative treatment for primary HCC (IFN group), were compared with 42 matched curatively treated historical controls not given IFN (nonIFN group). RESULTS: Although the rate of initial recurrence did not differ significantly between IFN group and non-IFN group (0%, 44%, 61%, and 67% vs 4.8%, 53%, 81%, and 87% at 1, 3, 5, and 7 years, P = 0.153, respectively), IFN group showed a lower rate than the non-IFN group for second recurrence (0%, 10.4%, 28%, and 35% vs 0%, 30%, 59%, and 66% at 1, 3, 5 and 7 years, P = 0.022, respectively). Among the IFN group, patients with sustained virologic response (SVR) were less likely to have a second HCC recurrence than IFN patients without an SVR, or non-IFN patients. Multivariate analysis identified the lack of SVR as the only independent risk factor for a second recurrence, while SVR and Child-Pugh class A independently favored overall survival. CONCLUSION: Most intrahepatic recurrences of HCVrelated HCC occurred during persistent viral infection. Eradication of HCV is essential for the prevention of HCC recurrence and improvement of survival.