A 41-year-old woman with chronic hepatitis C was treated with pegylated-interferon (PEG-IFN)-α-2b plus ribavirin for 24 weeks. She had hepatitis C virus (HCV) genotype 2a (1600 KIU/mL), and her liver histology showed mild inflammation and fibrosis. Four weeks after the start of the therapy, she achieved a rapid virological response (RVR) and then a sustained virological response (SVR). Serum alanine aminotransferase (ALT) levels remained within normal ranges and HCV RNA continued to be negative. However, ALT levels flared with the re-emergence of HCV RNA in the serum 1.5 years after discontinuation of therapy. HCV RNA obtained from sera before therapy and after relapse shared a 98.6% homology with the E2 region, and phylogenetic analyses indicated that they were the same HCV strain. These results eliminated the possibility of a re-infection and strongly indicated a late relapse of the disease. Therefore, follow-up is necessary for chronic hepatitis C patients after SVR, even if they respond well to therapy, including RVR.