The risk factors for the development of hepatocellular carcinoma (HCC) in patients who have achieved a long-term sustained viral response (SVR) to interferon (IFN) are not fully understood. This study aimed to investigate the characteristics of patients who developed HCC after 10 years of achieving SVR. We retrospectively studied 5 patients with HCC which developed more than 10 years after the termination of IFN therapy. The clinical characteristics at the induction of IFN therapy were male gender, a mean age of 51.6±9.1 years, while 2 patients were moderate alcohol consumers. None of the 5 patients were positive for either HBs Ag or anti-HBc Ab. A histological examination at the initial IFN therapy showed the activity scores to be A2 in all cases, and the fibrosis scores at least F2. The clinical parameters at the diagnosis of HCC included fluctuating transaminase levels in all cases. These levels scarcely fell below the upper limits even after SVR was achieved. In 3 patients, liver tissues were obtained at the treatment of HCC. These tissues showed marked improvement in both activities and fibroses, but severe steatosis in 1 patient. To conclude, chronic hepatitis C patients who respond to IFN therapy should undergo long-term follow-up, even after the eradication of HCV, with special attention particularly to patients who had elevated transaminase levels and steatosis.