The viral load of different hepatitis C virus (HCV) subtypes, including the globally distributed HCV-1b and the unique Indonesian subtype HCV-1c, was analyzed using serum samples obtained from Indonesian blood donors and patients with chronic liver disease. The mean viral load of HCV-1c was comparable with that of HCV-1b, suggesting that HCV-1c is as pathogenic as HCV-1b. On the other hand, the mean viral load of HCV-2a was lower than that of HCV-1b or HCV-1c, with this result being consistent with previous observations. Interestingly, some HCV-2a strains were associated with a high viral load that was almost equivalent to that of HCV-1b and HCV-1c. This result implies the possibility that there exists a minor fraction of HCV-2a strains that cause higher levels of viremia compared with the majority of ordinary HCV-2a strains.