To determine whether serum hepatitis C virus (HCV) RNA disappearance after interferon (IFN) treatment prevents development of hepatocellular carcinoma (HCC), we evaluated retrospectively the incidence of HCC in patients with chronic hepatitis C. A total of 213 patients were monitored for more than 6 months after completion of IFN treatment. Sixty-three of the 213 patients (29.6%) achieved a complete response (CR) to treatment and 150 (70.4%) had no response (NR). HCC developed in 12 (5.6%), all of whom were NR. Logistic analysis showed age, alpha -fetoprotein, and staging of histological finding before IFN treatment were independent factors to development of HCC. The fact that there was no HCC development from CR provides a basis for IFN treatment in chronic HCV infection.