Background: Serum hepatitis C virus (HCV) RNA levels and genotypes are considered to be important determinants of the response to interferon treatment. Generally, patterns of viral loads have been reported for HCV type 1 infections and categorized as low- or high-level viremia. We studied the distribution of HCV RNA levels in patients predominantly infected with HCV type 3 and correlated it with hepatic damage. Methods: Serum HCV RNA levels and HCV serotypes were determined in 245 anti-HCV-positive patients representing all the major ethnic groups of Pakistan. Patients were grouped according to their HCV RNA levels as: level I (up to 50th percentile); level II (50th to 75th percentile); and level III (>75th percentile). Results: Sixty-one patients (25%) had high-level viremia (level III) of 13.9 mega equivalent per milliliter (MEq/mL) or greater. These were more likely to be males (48 versus 13, P<0.05). A higher viral load correlated with advanced levels of fatty changes in liver. HCV type 3 was found in 68% of the samples, and type 1 in 14%; the rest were undefined. Mean HCV RNA levels were lower in patients infected with HCV type 3 than in patients infected with HCV type 1 (8.63 MEq/mL versus 37 MEq/mL; P<0.001). Conclusions: Most patients with HCV type 3 infection had viremia that was significantly lower than that in HCV type 1-infected patients. This may be the reason for the better response to treatment usually seen in such cases. The severity of histologic changes was not associated with HCV type 3 viremia levels.